Prepare a report on modern methods of studying the Universe. Physiology methods

Municipal educational institution

secondary school №37

Human Genetic Research Methods

Smolensk 2010

Introduction

1. Genetics as a science

1.1 The main stages in the development of genetics

1.2 Main tasks of genetics

1.3 Main sections of genetics

1.4 Influence of genetics on other branches of biology

2. Human genetics (anthropogenetics)

3.Methods for studying heredity

3.1 Genealogical method

3.2 Twin method

3.3 Cytogenetic (karyotypic) methods

3.4 Biochemical methods

3.5 Population methods

Conclusion

Literature

Application

Introduction

If the 19th century rightfully entered the history of world civilization as the Age of Physics, then the rapidly ending century of the 20th century, in which we were lucky to live, in all likelihood, is destined for the Age of Biology, and perhaps the Age of Genetics.

Indeed, in less than 100 years after the second discovery of the laws of G. Mendel, genetics has gone a triumphant path from the natural-philosophical understanding of the laws of heredity and variability through the experimental accumulation of the facts of formal genetics to the molecular biological understanding of the essence of the gene, its structure and function. From theoretical constructions about a gene as an abstract unit of heredity to understanding its material nature as a fragment of a DNA molecule encoding the amino acid structure of a protein, to cloning individual genes, creating detailed genetic maps of humans and animals, identifying genes whose mutations are associated with hereditary ailments, developing methods of biotechnology and genetic engineering, which makes it possible to purposefully obtain organisms with given hereditary traits, as well as to carry out directed correction of mutant human genes, i.e. gene therapy for hereditary diseases. Molecular genetics has significantly deepened our understanding of the essence of life, the evolution of wildlife, structural and functional mechanisms of regulation individual development. Thanks to its success, the solution of the global problems of mankind related to the protection of its gene pool has begun.

The middle and second half of the 20th century was marked by a significant decrease frequency and even the complete elimination of a number of infectious diseases, reducing infant mortality, increasing life expectancy. In the developed countries of the world, the focus of health care services has been shifted to the fight against chronic human pathology, diseases of the cardiovascular system, and oncological diseases.

Goals and objectives of my essay:

· Consider the main stages of development, tasks and goals of genetics;

· Give a precise definition of the term "human genetics" and consider the essence of this type of genetics;

· Consider methods for studying human heredity.

1. Genetics as a science

1 The main stages in the development of genetics

The origins of genetics, like any science, should be sought in practice. Genetics arose in connection with the breeding of domestic animals and the cultivation of plants, as well as with the development of medicine. Since man began to use the crossing of animals and plants, he was faced with the fact that the properties and characteristics of the offspring depend on the properties of the parent individuals chosen for crossing. By selecting and crossing the best descendants, from generation to generation, a person created related groups - lines, and then breeds and varieties with hereditary properties characteristic of them.

Although these observations and comparisons could not yet become the basis for the formation of science, the rapid development of animal husbandry and breeding, as well as crop and seed production in the second half of the 19th century, gave rise to an increased interest in the analysis of the phenomenon of heredity.

The development of the science of heredity and variability was especially strongly promoted by Charles Darwin's theory of the origin of species, which introduced the historical method of studying the evolution of organisms into biology. Darwin himself put a lot of effort into the study of heredity and variability. He collected a huge amount of facts, made a number of correct conclusions on their basis, but he failed to establish the laws of heredity.

His contemporaries, the so-called hybridizers, who crossed various forms and looking for the degree of similarity and difference between parents and offspring, also failed to establish the general patterns of inheritance.

Another condition that contributed to the development of genetics as a science was advances in the study of the structure and behavior of somatic and germ cells. Back in the 70s of the last century, a number of cytological researchers (Chistyakov in 1972, Strasburger in 1875) discovered indirect somatic cell division, called karyokinesis (Schleicher in 1878) or mitosis (Flemming in 1882) . The permanent elements of the cell nucleus in 1888, at the suggestion of Valdeyre, were called "chromosomes". In the same years, Flemming broke the entire cycle of cell division into four main phases: prophase, metaphase, anaphase and telophase.

Simultaneously with the study of somatic cell mitosis, studies were underway on the development of germ cells and the mechanism of fertilization in animals and plants. O. Hertwig in 1876 for the first time in echinoderms establishes the fusion of the nucleus of the spermatozoon with the nucleus of the egg. N.N. Gorozhankin in 1880 and E. Strasburger in 1884 established the same for plants: the first - for gymnosperms, the second - for angiosperms.

In the same van Beneden (1883) and others, the cardinal fact is revealed that in the process of development, sex cells, unlike somatic cells, undergo a reduction in the number of chromosomes exactly by half, and during fertilization - the fusion of the female and male nuclei - the normal number of chromosomes is restored , constant for each species. Thus, it was shown that a certain number of chromosomes is characteristic of each species.

So, these conditions contributed to the emergence of genetics as a separate biological discipline - a discipline with its own subject and methods of research.

The spring of 1900 is considered to be the official birth of genetics, when three botanists, independently of each other, in three different countries, at different objects, came to the discovery of some of the most important patterns of inheritance of traits in the offspring of hybrids. G. de Vries (Holland), on the basis of work with evening primrose, poppy, dope and other plants, reported "the law of splitting of hybrids"; K. Korrens (Germany) established patterns of splitting in corn and published an article "Gregor Mendel's law on the behavior of offspring in racial hybrids"; in the same year, K. Cermak (Austria) published an article (On artificial crossing in Pisum Sativum).

Science knows almost no unexpected discoveries. The most brilliant discoveries, creating stages in its development, almost always have their predecessors. This is what happened with the discovery of the laws of heredity. It turned out that the three botanists who discovered the pattern of splitting in the offspring of intraspecific hybrids merely "rediscovered" the patterns of inheritance discovered back in 1865 by Gregor Mendel and set forth by him in the article "Experiments on Plant Hybrids" published in the "Proceedings" of the Society of Naturalists in Brunn (Czechoslovakia).

G. Mendel developed methods for genetic analysis of the inheritance of individual traits of an organism on pea plants and established two fundamentally important phenomena:

Signs are determined by individual hereditary factors that are transmitted through germ cells;

Separate characteristics of organisms do not disappear during crossing, but are preserved in the offspring in the same form in which they were in the parent organisms.

For the theory of evolution, these principles were of cardinal importance. They uncovered one of the most important sources of variability, namely, the mechanism for maintaining the fitness of the traits of a species in a number of generations. If the adaptive traits of organisms, which arose under the control of selection, were absorbed, disappeared during crossing, then the progress of the species would be impossible.

All subsequent development of genetics has been associated with the study and extension of these principles and their application to the theory of evolution and selection.

From the established fundamental provisions of Mendel, a number of problems logically follow, which, step by step, are being resolved as genetics develops. In 1901, de Vries formulated the theory of mutations, which states that the hereditary properties and characteristics of organisms change in leaps and bounds - mutations.

In 1903, the Danish plant physiologist W. Johannsen published his work "On Inheritance in Populations and Pure Lines", in which it was experimentally established that outwardly similar plants belonging to the same variety are hereditarily different - they constitute a population. The population consists of hereditarily different individuals or related groups - lines. In the same study, the existence of two types of variability in organisms is most clearly established: hereditary, determined by genes, and non-hereditary, determined by a random combination of factors acting on the manifestation of traits.

At the next stage in the development of genetics, it was proved that hereditary forms are associated with chromosomes. The first fact revealing the role of chromosomes in heredity was the proof of the role of chromosomes in sex determination in animals and the discovery of the 1:1 sex splitting mechanism.

Since 1911, T. Morgan with colleagues at Columbia University in the USA began to publish a series of works in which he formulated the chromosome theory of heredity. Experimentally proving that the main carriers of genes are chromosomes, and that genes are located linearly in chromosomes.

In 1922 N.I. Vavilov formulates the law of homological series in hereditary variability, according to which species of plants and animals related in origin have similar series of hereditary variability.

Applying this law, N.I. Vavilov established the centers of origin of cultivated plants, in which the greatest variety of hereditary forms is concentrated.

In 1925, in our country, G.A. Nadson and G.S. Filippov on mushrooms, and in 1927 G. Möller in the USA on the Drosophila fruit fly obtained evidence of the influence of X-rays on the occurrence of hereditary changes. It was shown that the rate of mutations increases by more than 100 times. These studies have proved the variability of genes under the influence of environmental factors. Proof of Influence ionizing radiation on the occurrence of mutations led to the creation of a new branch of genetics - radiation genetics, the importance of which has grown even more with the discovery of atomic energy.

In 1934, T. Painter, on the giant chromosomes of the salivary glands of Diptera, proved that the discontinuity of the morphological structure of chromosomes, expressed in the form of various disks, corresponds to the arrangement of genes in chromosomes, previously established by purely genetic methods. This discovery laid the foundation for the study of the structure and functioning of the gene in the cell.

In the period from the 1940s to the present, a number of discoveries (mainly on microorganisms) of completely new genetic phenomena have been made, which have opened up the possibilities of analyzing the structure of a gene at the molecular level. In recent years, with the introduction of new research methods into genetics, borrowed from microbiology, we have come to unravel how genes control the sequence of amino acids in a protein molecule.

First of all, it should be said that it has now been fully proven that the carriers of heredity are chromosomes, which consist of a bundle of DNA molecules.

Quite simple experiments were carried out: from the killed bacteria of one strain, which had a special external feature, pure DNA was isolated and transferred to living bacteria of another strain, after which the multiplying bacteria of the latter acquired the feature of the first strain. Such numerous experiments show that it is DNA that is the carrier of heredity.

In 1953, F. Crick (England) and J. Watstone (USA) deciphered the structure of the DNA molecule. They found that each DNA molecule is made up of two polydeoxyribonucleic chains, spirally twisted around a common axis.

At present, approaches have been found to solving the problem of organizing the hereditary code and its experimental decoding. Genetics, together with biochemistry and biophysics, came close to elucidating the process of protein synthesis in a cell and the artificial synthesis of a protein molecule. This starts completely new stage development not only of genetics, but of all biology as a whole.

The development of genetics to the present day is a continuously expanding fund of research on the functional, morphological and biochemical discreteness of chromosomes. A lot has already been done in this area, a lot has already been done, and every day the cutting edge of science is approaching the goal - unraveling the nature of the gene. To date, a number of phenomena characterizing the nature of the gene have been established. First, the gene in the chromosome has the property of self-reproducing (self-reproduction); secondly, it is capable of mutational change; thirdly, it is associated with a certain chemical structure of deoxyribonucleic acid - DNA; fourthly, it controls the synthesis of amino acids and their sequences in a protein molecule. In connection with recent studies, a new idea of ​​the gene as a functional system is being formed, and the effect of the gene on determining traits is considered in an integral system of genes - the genotype.

The opening prospects for the synthesis of living matter attract great attention of geneticists, biochemists, physicists and other specialists.

1.2 Main tasks of genetics

genetics biology heredity genealogical

Genetic research pursues goals of two kinds: knowledge of the laws of heredity and variability, and the search for ways to use these laws in practice. Both are closely related: the solution of practical problems is based on the conclusions obtained in the study of fundamental genetic problems and at the same time provides factual data that are important for expanding and deepening theoretical concepts.

From generation to generation, information is transmitted (although sometimes in a somewhat distorted form) about all the diverse morphological, physiological and biochemical traits that should be realized in descendants. Based on this cybernetic nature of genetic processes, it is convenient to formulate four main theoretical problems investigated by genetics:

First, the problem of storing genetic information. It is studied in which material structures of the cell the genetic information is contained and how it is encoded there.

Secondly, the problem of transfer of genetic information. The mechanisms and patterns of transmission of genetic information from cell to cell and from generation to generation are studied.

Thirdly, the problem of realization of genetic information. It is studied how genetic information is embodied in specific traits of a developing organism, while interacting with the influences of the environment, which to some extent changes these traits, sometimes significantly.

Fourth, the problem of changing genetic information. The types, causes and mechanisms of these changes are studied.

Achievements in genetics are used to select the types of crosses that best affect the genotypic structure (splitting) in offspring, to select the most effective ways selection, to regulate the development of hereditary traits, control the mutation process, targeted changes in the genome of an organism using genetic engineering and site-specific mutagenesis. Knowing how different selection methods affect the genotypic structure of the initial population (breed, variety) allows you to use those selection methods that will most quickly change this structure in the desired direction. Understanding the ways of realization of genetic information in the course of ontogenesis and the influence exerted on these processes by the environment helps to select the conditions conducive to the most complete manifestation of valuable traits in a given organism and the “suppression” of undesirable ones. This is important for increasing the productivity of domestic animals, cultivated plants and industrial microorganisms, as well as for medicine, as it helps to prevent the manifestation of a number of human hereditary diseases.

The study of physical and chemical mutagens and their mechanism of action makes it possible to artificially obtain many hereditarily modified forms, which contributes to the creation of improved strains of beneficial microorganisms and varieties of cultivated plants. Knowledge of the regularities of the mutation process is necessary for developing measures to protect the human and animal genome from damage by physical (chiefly, radiation) and chemical mutagens.

The success of any genetic research is determined not only by knowledge of the general laws of heredity and variability, but also by knowledge of the particular genetics of the organisms with which work is being done. Although the basic laws of genetics are universal, they also have features in different organisms due to differences, for example, in the biology of reproduction and the structure of the genetic apparatus. In addition, for practical purposes, it is necessary to know which genes are involved in determining the characteristics of a given organism. Therefore, the study of the genetics of specific traits of an organism is required element applied research.

3 Main sections of genetics

Modern genetics is represented by many sections of both theoretical and practical interest. Among the sections of general, or "classical" genetics, the main ones are: genetic analysis, the basics of the chromosome theory of heredity, cytogenetics, cytoplasmic (extranuclear) heredity, mutations, modifications. Molecular genetics, genetics of ontogeny (phenogenetics), population genetics (genetic structure of populations, the role of genetic factors in microevolution), evolutionary genetics (the role of genetic factors in speciation and macroevolution), genetic engineering, genetics of somatic cells, immunogenetics, private genetics - genetics are intensively developing. bacteria, virus genetics, animal genetics, plant genetics, human genetics, medical genetics, and more. etc. The latest branch of genetics - genomics - studies the processes of formation and evolution of genomes.

4 Influence of genetics on other branches of biology

Genetics occupies a central place in modern biology, studying the phenomena of heredity and variability, which to a greater extent determine all the main properties of living beings. The universality of the genetic material and the genetic code underlies the unity of all living things, and the diversity of life forms is the result of the peculiarities of its implementation in the course of the individual and historical development of living beings. Achievements in genetics are an important part of almost all modern biological disciplines. The synthetic theory of evolution is the closest combination of Darwinism and genetics. The same can be said about modern biochemistry, whose main provisions on how the synthesis of the main components of living matter - proteins and nucleic acids - are controlled, are based on the achievements of molecular genetics. Cytology focuses on the structure, reproduction, and functioning of chromosomes, plastids, and mitochondria, i.e., elements in which genetic information is recorded. The taxonomy of animals, plants, and microorganisms is increasingly using the comparison of genes encoding enzymes and other proteins, as well as direct comparison of the nucleotide sequences of chromosomes to establish the degree of relationship of taxa and elucidate their phylogeny. Various physiological processes in plants and animals are studied in genetic models; in particular, in studies of the physiology of the brain and nervous system, they use special genetic methods, lines of Drosophila and laboratory mammals. Modern immunology is entirely based on genetic data on the mechanism of antibody synthesis. Achievements in genetics, to one degree or another, often very significant, are an integral part of virology, microbiology, and embryology. It can rightly be said that modern genetics occupies a central place among biological disciplines.

2. Human genetics (anthropogenetics)

1. Methods for studying human heredity: genealogical, twin, cytogenetic, biochemical and population

Genetic diseases and hereditary diseases. The value of medical genetic counseling and prenatal diagnosis. Possibilities of genetic correction of diseases.

Human genetics is a special branch of genetics that studies the features of inheritance of traits in humans, hereditary diseases (medical genetics), and the genetic structure of human populations. Human genetics is the theoretical basis of modern medicine and modern healthcare.

It is now firmly established that in the living world the laws of genetics are of a universal nature, and they are also valid for humans.

However, since a person is not only a biological, but also a social being, human genetics differs from the genetics of most organisms in a number of ways: - hybridological analysis (crossing method) is not applicable to study human inheritance; therefore, specific methods are used for genetic analysis: genealogical (pedigree analysis method), twin, as well as cytogenetic, biochemical, population and some other methods;

characteristic of humans social signs that are not found in other organisms, for example, temperament, complex communication systems based on speech, as well as mathematical, visual, musical and other abilities;

thanks to public support, the survival and existence of people with obvious deviations from the norm is possible (in the wild, such organisms are not viable).

Human genetics studies the features of inheritance of traits in humans, hereditary diseases (medical genetics), the genetic structure of human populations. Human genetics is the theoretical basis of modern medicine and modern healthcare. Several thousand actually genetic diseases are known, which are almost 100% dependent on the genotype of the individual. The most terrible of them include: acid fibrosis of the pancreas, phenylketonuria, galactosemia, various forms of cretinism, hemoglobinopathies, as well as Down, Turner, Klinefelter syndromes. In addition, there are diseases that depend on both the genotype and the environment: ischemic disease, diabetes, rheumatoid diseases, peptic ulcer stomach and duodenum, many cancers, schizophrenia and other mental illnesses.

The tasks of medical genetics are to timely identify carriers of these diseases among parents, identify sick children and develop recommendations for their treatment. An important role in the prevention of genetically determined diseases is played by genetic medical consultations and prenatal diagnostics (that is, the detection of diseases in the early stages of development of the body).

There are special sections of applied human genetics (environmental genetics, pharmacogenetics, genetic toxicology) that study the genetic foundations of health care. When developing drugs, when studying the body's response to the impact of adverse factors, it is necessary to take into account both the individual characteristics of people and the characteristics of human populations.

Let us give examples of the inheritance of some morphophysiological traits.

Dominant and recessive traits in humans

(for some traits, the genes controlling them are indicated) (Table No. 1 see pr.)

Incomplete dominance (the genes that control the trait are indicated) (Table No. 2 see pr.)

Inheritance of hair color (controlled by four genes, inherited polymerically) (Table No. 3. See pr.)

3. Methods for studying human heredity

A pedigree is a diagram that reflects the relationships between family members. Analyzing pedigrees, they study any normal or (more often) pathological trait in the generations of people who are related.

3.1 Genealogical methods

Genealogical methods are used to determine the hereditary or non-hereditary nature of a trait, dominance or recessiveness, chromosome mapping, sex linkage, to study the mutation process. As a rule, the genealogical method forms the basis for conclusions in medical genetic counseling.

When compiling pedigrees, standard notation is used. The person (individual) from whom the study begins is called the proband (if the pedigree is compiled in such a way that descend from the proband to its offspring, then it is called the family tree). The offspring of a married couple is called a sibling, siblings are called siblings, cousins ​​are called cousins, and so on. Descendants who have a common mother (but different fathers) are called consanguineous, and descendants who have a common father (but different mothers) are called consanguineous; if the family has children from different marriages, and they do not have common ancestors (for example, a child from the mother’s first marriage and a child from the father’s first marriage), then they are called consolidated.

Each member of the pedigree has its own cipher, consisting of a Roman numeral and an Arabic one, denoting the generation number and the individual number, respectively, with the generations numbered sequentially from left to right. With a pedigree, there should be a legend, that is, an explanation of the accepted designations. In closely related marriages, there is a high probability of finding the same unfavorable allele or chromosomal aberration in spouses.

Here are the values ​​of K for some pairs of relatives in monogamy:

K [parent-children]=K [siblings]=1/2;

K [grandfather-grandson] = K [uncle-nephew] = 1/4;

K [cousins] = K [great-grandfather-great-grandson] = 1/8;

K [second cousins]=1/32;

K [fourth cousins] = 1/128. Usually such distant relatives within the same family are not considered.

Based on the genealogical analysis, a conclusion is made about the hereditary conditionality of the trait. For example, the inheritance of hemophilia A among the descendants of Queen Victoria of England has been traced in detail. Genealogical analysis has established that hemophilia A is a sex-linked recessive disease.

2 Twin method

Twins are two or more children conceived and born by the same mother at almost the same time. The term "twins" is used in relation to humans and those mammals who normally have one child (calf). There are identical and fraternal twins.

Identical (monozygous, identical) twins occur at the earliest stages of zygote cleavage, when two or four blastomeres retain the ability to develop into a full-fledged organism during isolation. Since the zygote divides by mitosis, the genotypes of identical twins, at least initially, are completely identical. Identical twins are always of the same sex and share the same placenta during fetal development.

Fraternal (dizygotic, non-identical) twins arise differently - when two or more simultaneously mature eggs are fertilized. Thus, they share about 50% of their genes. In other words, they are similar to ordinary brothers and sisters in their genetic constitution and can be either same-sex or different-sex.

Thus, the similarity between identical twins is determined by the same genotypes and the same conditions of intrauterine development. The similarity between fraternal twins is determined only by the same conditions of intrauterine development.

The birth rate of twins in relative terms is low and is about 1%, of which 1/3 are monozygotic twins. However, in terms of the total population of the Earth, there are over 30 million fraternal and 15 million identical twins in the world.

For studies on twins, it is very important to establish the reliability of zygosity. The most accurate zygosity is determined by reciprocal transplantation of small areas of skin. In dizygotic twins, grafts are always rejected, while in monozygotic twins, transplanted pieces of skin successfully take root. Transplanted kidneys, transplanted from one of the monozygotic twins to the other, function just as successfully and for a long time.

When comparing identical and fraternal twins raised in the same environment, one can draw a conclusion about the role of genes in the development of traits. The conditions of post-natal development for each of the twins may be different. For example, monozygotic twins were separated a few days after birth and raised in different conditions. Comparison of them after 20 years in many external features (height, head volume, number of grooves on fingerprints, etc.) revealed only minor differences. At the same time, the environment affects a number of normal and pathological signs.

The twin method allows you to make reasonable conclusions about the heritability of traits: the role of heredity, environment and random factors in determining certain traits of a person,

Heritability is the contribution of genetic factors to the formation of a trait, expressed as a fraction of a unit or a percentage.

To calculate the heritability of traits, the degree of similarity or difference in a number of traits in twins of different types is compared.

Let's consider some examples illustrating the similarity (concordance) and difference (discordance) of many features (Table No. 4. See pr.)

Attention is drawn to the high degree of similarity of identical twins in such serious diseases as schizophrenia, epilepsy, and diabetes mellitus.

In addition to morphological features, as well as the timbre of voice, gait, facial expressions, gestures, etc., they study the antigenic structure of blood cells, serum proteins, and the ability to taste certain substances.

Of particular interest is the inheritance of socially significant traits: aggressiveness, altruism, creative, research, organizational skills. It is believed that socially significant signs are approximately 80% determined by the genotype.

3 Cytogenetic (karyotypic) methods

Cytogenetic methods are used, first of all, in the study of karyotypes of individual individuals. The human karyotype is quite well studied. The use of differential staining allows you to accurately identify all chromosomes. The total number of chromosomes in the haploid set is 23. Of these, 22 chromosomes are the same in both men and women; they are called autosomes. In the diploid set (2n=46), each autosome is represented by two homologues. The twenty-third chromosome is the sex chromosome, it can be represented by either the X or Y chromosome. The sex chromosomes in females are represented by two X chromosomes, and in males, one X chromosome and one Y chromosome.

Changes in the karyotype are usually associated with the development of genetic diseases.

Thanks to the cultivation of human cells in vitro, it is possible to quickly obtain a sufficiently large material for the preparation of preparations. For karyotyping, a short-term culture of peripheral blood leukocytes is usually used.

Cytogenetic methods are also used to describe interphase cells. For example, by the presence or absence of sex chromatin (Barr bodies, which are inactivated X chromosomes), it is possible not only to determine the sex of individuals, but also to identify some genetic diseases associated with a change in the number of X chromosomes.

Mapping of human chromosomes.

Biotechnology methods are widely used to map human genes. In particular, cell engineering methods make it possible to combine different types cells. The fusion of cells belonging to different biological species is called somatic hybridization. The essence of somatic hybridization is to obtain synthetic cultures by fusion of protoplasts various kinds organisms. Various physicochemical and biological methods are used for cell fusion. After the fusion of protoplasts, multinucleated heterokaryotic cells are formed. Subsequently, during the fusion of the nuclei, synkarotic cells are formed, containing chromosome sets of different organisms in the nuclei. When such cells divide in vitro, hybrid cell cultures are formed. At present, cell hybrids "human × mouse, human × rat" and many others.

In hybrid cells obtained from different strains different types, one of the parental genomes gradually loses chromosomes. These processes proceed intensively, for example, in cell hybrids between mice and humans. If, at the same time, some biochemical marker (for example, a certain human enzyme) is monitored and cytogenetic control is carried out simultaneously, then, in the end, it is possible to associate the disappearance of a chromosome simultaneously with a biochemical trait. This means that the gene encoding this trait is localized on this chromosome.

Additional information about the localization of genes can be obtained by analyzing chromosomal mutations (deletions).

4 Biochemical methods

The whole variety of biochemical methods is divided into two groups:

a) Methods based on the identification of certain biochemical products due to the action of different alleles. The easiest way to identify alleles is by changing the activity of enzymes or by changing any biochemical trait.

b) Methods based on the direct detection of altered nucleic acids and proteins using gel electrophoresis in combination with other methods (blot hybridization, autoradiography).

The use of biochemical methods makes it possible to identify heterozygous carriers of diseases. For example, in heterozygous carriers of the phenylketonuria gene, the level of phenylalanine in the blood changes.

Mutagenesis Genetics Methods

The mutation process in humans in humans, as in all other organisms, leads to the emergence of alleles and chromosomal rearrangements that adversely affect health.

Gene mutations. About 1% of newborns fall ill due to gene mutations, some of which are newly emerging. The rate of mutation of various genes in the human genotype is not the same. Genes are known that mutate at a rate of 10-4 per gamete per generation. However, most other genes mutate at hundreds of times less frequency (10-6). Below are examples of the most common gene mutations in humans (Table No. 5. see pr.)

Chromosomal and genomic mutations in the absolute majority occur in the germ cells of the parents. One in 150 newborns carries a chromosomal mutation. About 50% of early abortions are due to chromosomal mutations. This is due to the fact that one of 10 human gametes is a carrier of structural mutations. The age of parents, especially the age of mothers, plays an important role in increasing the frequency of chromosomal and possibly gene mutations.

Polyploidy is very rare in humans. Triploid births are known - these newborns die early. Tetraploids were found among aborted embryos.

At the same time, there are factors that reduce the frequency of mutations - antimutagens. Antimutagens include some antioxidant vitamins (for example, vitamin E, unsaturated fatty acids), sulfur-containing amino acids, and various biologically active substances that increase the activity of repair systems.

5 Population methods

The main features of human populations are: the common territory on which a given group of people lives, and the possibility of free marriage. Factors of isolation, i.e., restrictions on the freedom of choice of spouses, for a person can be not only geographical, but also religious and social barriers.

In human populations, there is a high level of polymorphism in many genes: that is, the same gene is represented by different alleles, which leads to the existence of several genotypes and corresponding phenotypes. Thus, all members of a population differ from each other genetically: it is practically impossible to find even two genetically identical people in a population (with the exception of identical twins).

Various forms of natural selection operate in human populations. Selection acts both in the prenatal state and in subsequent periods of ontogeny. The most pronounced stabilizing selection is directed against unfavorable mutations (for example, chromosomal rearrangements). A classic example of selection in favor of heterozygotes is the spread of sickle cell anemia.

Population methods allow us to estimate the frequencies of the same alleles in different populations. In addition, population methods make it possible to study the mutation process in humans. By the nature of radiosensitivity, the human population is genetically heterogeneous. In some people with genetically determined defects in DNA repair, the radiosensitivity of chromosomes is increased by 5–10 times compared to most members of the population.

Conclusion

So, to adequately perceive the revolution taking place before our eyes in biology and medicine, to be able to take advantage of its tempting fruits and avoid temptations dangerous for humanity - this is what doctors, biologists, representatives of other specialties, and just an educated person need today.

Protecting the gene pool of mankind, protecting it in every possible way from risky interventions, and at the same time extracting the maximum benefit from the invaluable information already received in terms of diagnosis, prevention and treatment of many thousands of hereditary ailments - this is the task that needs to be addressed today and with which we will enter a new 21st century.

In my abstract, I set the tasks that I needed to consider. I learned more about genetics. Learn what genetics is. Considered its main stages of development, tasks and goals of modern genetics. I also considered one of the varieties genetics - genetics person. She gave a precise definition of this term and considered the essence of this type of genetics. Also in my essay, we examined the types of study of human heredity. Their varieties and the essence of each method.

Literature

·Encyclopedia. Human. volume 18. part one. Volodin V.A. - M.: Avolta +, 2002;

·Biology. General patterns. Zakharov V.B., Mamontov S.G., Sivoglazov V.I. - M.: School-Press, 1996;

·<#"justify">Application

Table No. 1 Dominant and recessive traits in humans (for some traits, their controlling genes are indicated)

ДоминантныеРецессивныеНормальная пигментация кожи, глаз, волосАльбинизмБлизорукостьНормальное зрениеНормальное зрениеНочная слепотаЦветовое зрениеДальтонизмКатарактаОтсутствие катарактыКосоглазиеОтсутствие косоглазияТолстые губыТонкие губыПолидактилия (добавочные пальцы)Нормальное число пальцевБрахидактилия (короткие пальцы)Нормальная длина пальцевВеснушкиОтсутствие веснушекНормальный слухВрожденная глухотаКарликовостьНормальный ростНормальное усвоение глюкозыСахарный диабетНормальная свертываемость кровиГемофилияКруглая форма лица (R-)Квадратная форма лица (rr) Dimple on the chin (A-) No dimple (aa) Dimples on the cheeks (D-) No dimple (dd) Thick eyebrows (B-) Thin eyebrows (bb) Eyebrows do not connect (N-) Eyebrows connect (nn) Long eyelashes ( L-) Short eyelashes (ll) Round nose (G-) Pointy nose (gg) Round nostrils (Q-) Narrow nostrils (qq)

Table No. 2Incomplete dominance (the genes that control the trait are indicated)

Signs Variants Distance between the eyes - TLargeMediumSmall Eye size - ELargeMediumSmall Mouth size - MLargeMediumSmall Hair type - Curly CurlyStraight Eyebrow color - Night darkDarkLightNose size - FLargeMediumSmall Table No. 3 Inheritance of hair color (controlled by four genes, inherited polymerically)

Number of dominant alleles Hair color 8 Black 7 Dark brown 6 Dark chestnut 5 Chestnut 4 Light blond 3 Light blond 2 Blond 1 Very light blond 0 White

Table No. 4

a) The degree of difference (discordance) in a number of neutral traits in twins

Traits controlled by a small number of genesFrequency (probability) of differences, %Heritability, % identical fraternal Eye color 0.57299 Ear shape 2.08098 Hair color 3.07796 Papillary lines 8.06087 mean< 1 %≈ 55 %95 %Биохимические признаки0,0от 0 до 100100 %Цвет кожи0,055Форма волос0,021Форма бровей0,049Форма носа0,066Форма губ0,035

b) The degree of similarity (concordance) for a number of diseases in twins

Traits controlled by a large number of genes and dependent on non-genetic factors Frequency of similarity, %Heritability, % identical fraternal Mental retardation 973795 Schizophrenia 691066 Diabetes mellitus 651857 Epilepsy 673053 average ≈ 70 % ≈ 20 % ≈ 65 % Crime (?) 682856 %

Table No. 5

Types and names of mutationsMutation frequency (per 1 million gametes)Autosomal dominantPolycystic kidney disease65...120Neurofibromatosis65...120Multiple colon polyposis10...50Pelger leukocyte anomaly9...27Osteogenesis imperfecta7...13Marfan's syndrome4...6Autosomal recessiveMicrocephaly27Ichthyosis ( not sex-linked) 11 Recessive, sex-linked Duchenne muscular dystrophy 43 ... 105 Hemophilia A37 ... 52 Hemophilia B2 ... 3 Ichthyosis (sex-linked) 24

Short description:

Sazonov V.F. Modern research methods in biology [ Electronic resource] // Kinesiologist, 2009-2018: [website]. Date of update: 22.02.2018..__.201_). Materials on modern research methods in biology, its sections and related disciplines.

Materials on modern research methods in biology, its sections and related disciplines

Picture In: The main branches of biology.

Currently, biology is conditionally divided into two large groups of sciences.

Biology of organisms: sciences about plants (botany), animals (zoology), fungi (mycology), microorganisms (microbiology). These sciences study individual groups of living organisms, their internal and external structure, lifestyle, reproduction and development.

General biology: molecular level (molecular biology, biochemistry and molecular genetics), cellular (cytology), tissue (histology), organs and their systems (physiology, morphology and anatomy), populations and natural communities (ecology). In other words, general biology studies life at various levels.

Biology is closely related to other natural sciences. So, at the junction between biology and chemistry, biochemistry and molecular biology appeared, between biology and physics - biophysics, between biology and astronomy - space biology. Ecology, which is at the intersection of biology and geography, is now often considered as an independent science.

Tasks of students in the training course Modern methods of biological research

1. Acquaintance with a variety of research methods in various fields of biology.

Decision and reporting:
1) Writing a review educational essay on research methods in various fields of biology. Minimum requirements for the content of the abstract: description of 5 research methods, 1-2 pages (font 14, spacing 1.5, margins 3-2-2-2 cm) for each method.
2) Presentation of a report (preferably in the form of a presentation) on one of the modern methods of biology: volume 5±1 page.
Expected learning outcomes:
1) Superficial acquaintance with a wide range of research methods in biology.
2) An in-depth understanding of one of the research methods and the transfer of this knowledge to the student group.

2. Conducting a teaching educational and scientific research from goal setting to conclusions using the necessary requirements for the design of a scientific research report.

Solution:
Obtaining primary data in laboratory classes and at home. It is allowed to conduct part of such a study in extracurricular time.

3. Acquaintance with general research methods in biology.

Solution:
Lecture course and independent work with sources of information. Report on the example of facts from the history of biology: volume 2±1 pages.

4. Application of the acquired knowledge, skills and abilities to conduct and design their own research in the form of research work, term paper and / or final qualifying work.

Definition of concepts

Research methods are ways to achieve the goal of the research work.

scientific method is a set of techniques and operations used in the construction of a system of scientific knowledge.

scientific fact - this is the result of observations and experiments, which establishes the quantitative and qualitative characteristics of objects.

Methodological basis scientific research is a set of methods scientific knowledge used to achieve the purpose of this study.

Methods are general scientific, experimental, methodological basis - .

Modern biology uses the unification of methodological approaches, it uses “the unity of descriptive-classifying and explanatory-nomothetic approaches; the unity of empirical research with the process of intensive theorization of biological knowledge, including its formalization, mathematization and axiomatization” [Yarilin A.A. "Cinderella" becomes a princess, or the place of biology in the hierarchy of sciences. // "Ecology and Life" No. 12, 2008. P. 4-11. S.11].

Objectives of research methods:

1. "Strengthening the natural cognitive abilities of man, as well as their expansion and continuation."

2. " Communicative function”, i.e. mediation between the subject and the object of study [Arshinov V.I. Synergetics as a phenomenon of post-non-classical science. M.: Institute of Philosophy RAS, 1999. 203 p. P.18].

General Research Methods in Biology

Observation

Observation - this is a study of external signs and visible changes in an object over a certain period of time. For example, observing the growth and development of a seedling.

Observation is the starting point of all natural science research.

In biology, this is especially noticeable, since the object of its study is man and the living nature surrounding him. Already at school, in the lessons of zoology, botany, and anatomy, children are taught to conduct the simplest biological research by observing the growth and development of plants and animals, and the state of their own body.

Observation as a method of collecting information is chronologically the very first method of research that appeared in the arsenal of biology, or rather, even its predecessor, natural history. And this is not surprising, since observation is based on the sensory abilities of a person (sensation, perception, representation). Classical biology is predominantly observational biology. But, nevertheless, this method has not lost its significance to this day.

Observations may be direct or indirect, with or without technical aids. So, an ornithologist sees a bird through binoculars and can hear it, or can fix sounds with the device outside the range audible to the human ear. A histologist observes a fixed and stained tissue section with a microscope. And for a molecular biologist, observation can be fixing a change in the concentration of an enzyme in a test tube.

It is important to understand that scientific observation, unlike ordinary, is not simple, but purposeful the study of objects or phenomena: it is carried out to solve the problem, and the attention of the observer should not be scattered. For example, if the task is to study the seasonal migrations of birds, then we will notice the timing of their appearance in nesting areas, and nothing else. So observation is selective allotment out of reality certain part, in other words, the aspect, and the inclusion of this part in the system under study.

In observation, not only the accuracy, accuracy and activity of the observer is important, but also his impartiality, his knowledge and experience, the right choice of technical means. The statement of the problem also presupposes the existence of an observation plan, i.e. their planning. [Kabakova D.V. Observation, description and experiment as the main methods of biology // Problems and prospects for the development of education: materials of the international. scientific conf. (Perm, April 2011). T. I. Perm: Mercury, 2011. S. 16-19.].

Descriptive Method

Descriptive Method - this is the fixation of the observed external signs of the objects of study with the allocation of the essential and the rejection of the insignificant. This method stood at the origins of biology as a science, but its development would have been impossible without the use of other research methods.

Descriptive methods allow you to first describe and then analyze the phenomena occurring in wildlife, compare them, finding certain patterns, as well as generalize, discover new types, classes, and so on. Descriptive methods began to be used in antiquity, but today they have not lost their relevance and are widely used in botany, ethology, zoology, etc.

Comparative method

Comparative method - this is a study of similarities and differences in the structure, course of life processes and the behavior of various objects. For example, a comparison of individuals of different sexes belonging to the same biological species.

Allows you to study the objects of study by comparing them with each other or with another object. Allows you to identify the similarities and differences of living organisms, as well as their parts. The data obtained make it possible to combine the studied objects into groups according to signs of similarity in structure and origin. On the basis of the comparative method, for example, the taxonomy of plants and animals is built. This method was also used to create the cell theory and to confirm the theory of evolution. Currently, it is used in almost all areas of biology.

This method was established in biology in the 18th century. and proved to be very fruitful in solving many of the biggest problems. With the help of this method and in combination with the descriptive method, information was obtained that allowed in the 18th century. lay the foundations for the taxonomy of plants and animals (K. Linnaeus), and in the 19th century. to formulate the cell theory (M. Schleiden and T. Schwann) and the doctrine of the main types of development (K. Baer). The method was widely used in the 19th century. in the substantiation of the theory of evolution, as well as in the restructuring of a number of biological sciences on the basis of this theory. However, the use of this method was not accompanied by the emergence of biology beyond the limits of descriptive science.
The comparative method is widely used in various biological sciences in our time. Comparison acquires special value when it is impossible to give a definition of the concept. For example, using an electron microscope, images are often obtained, the true content of which is not known in advance. Only their comparison with light microscopic images allows one to obtain the desired data.

historical method

Allows you to identify patterns of formation and development of living systems, their structures and functions, to compare them with previously known facts. This method, in particular, was successfully used by Charles Darwin to build his evolutionary theory and contributed to the transformation of biology from a descriptive science into an explanatory science.

In the second half of the XIX century. thanks to the works of Charles Darwin, the historical method put on scientific foundations the study of the patterns of appearance and development of organisms, the formation of the structure and functions of organisms in time and space. With the introduction of this method in biology, there have been significant qualitative changes. The historical method has transformed biology from a purely descriptive science into an explanatory science that explains how diverse living systems came into being and how they function. At present, the historical method, or "historical approach" has become a general approach to the study of the phenomena of life in all biological sciences.

experimental method

Experiment - this is a verification of the correctness of the put forward hypothesis with the help of a targeted impact on the object.

An experiment (experiment) is an artificial creation under controlled conditions of a situation that helps to reveal deeply hidden properties of living objects.

The experimental method of studying natural phenomena is associated with an active influence on them by conducting experiments (experiments) under controlled conditions. This method allows one to study phenomena in isolation and achieve repeatability of results when reproduced under the same conditions. The experiment provides a deeper, than other research methods, disclosure of the essence of biological phenomena. It is thanks to experiments that natural science in general and biology in particular have reached the discovery of the basic laws of nature.
Experimental methods in biology serve not only to conduct experiments and obtain answers to questions of interest, but also to determine the correctness of the hypothesis formulated at the beginning of the study of the material, as well as to correct it in the course of work. In the twentieth century, these research methods become leading in this science due to the advent of modern equipment for conducting experiments, such as, for example, a tomograph, electron microscope And so on. At present, biochemical methods, X-ray diffraction analysis, chromatography, as well as the technique of ultrathin sections, are widely used in experimental biology. various ways cultivation and many others. Experimental methods, combined with a systematic approach, have expanded the cognitive capabilities of biological science and opened up new roads for the application of knowledge in almost all areas of human activity.

The question of experiment as one of the foundations in the knowledge of nature was raised as early as the 17th century. English philosopher F. Bacon (1561-1626). His introduction to biology is associated with the work of W. Harvey in the 17th century. for the study of blood circulation. However, the experimental method became widely accepted in biology only in early XIX century, moreover, through physiology, in which they began to use a large number of instrumental methods that made it possible to register and quantitatively characterize the confinement of functions to structure. Thanks to the works of F. Magendie (1783-1855), G. Helmholtz (1821-1894), I.M. Sechenov (1829-1905), as well as the classics of the experiment C. Bernard (1813-1878) and I.P. Pavlova (1849-1936), physiology was probably the first of the biological sciences to become an experimental science.
Another direction in which the experimental method entered biology was the study of the heredity and variability of organisms. Here the main merit belongs to G. Mendel, who, unlike his predecessors, used the experiment not only to obtain data on the phenomena under study, but also to test the hypothesis formulated on the basis of the data obtained. The work of G. Mendel was a classic example of the methodology of experimental science.

In substantiating the experimental method, the work carried out in microbiology by L. Pasteur (1822-1895), who first introduced an experiment to study fermentation and refute the theory of spontaneous generation of microorganisms, and then to develop vaccination against infectious diseases, was of great importance. In the second half of the XIX century. Following L. Pasteur, R. Koch (1843-1910), D. Lister (1827-1912), I.I. Mechnikov (1845-1916), D.I. Ivanovsky (1864-1920), S.N. Vinogradsky (1856-1890), M. Beyernik (1851-1931) and others. In the 19th century. biology has also been enriched by the creation of the methodological foundations of modeling, which is also the highest form of experiment. The invention by L. Pasteur, R. Koch and other microbiologists of methods for infecting laboratory animals with pathogenic microorganisms and studying the pathogenesis of infectious diseases on them is a classic example of modeling that has passed into the 20th century. and supplemented in our time by modeling not only various diseases, but also various life processes, including the origin of life.
Starting, for example, from the 40s. 20th century The experimental method in biology has undergone significant improvement by increasing the resolution of many biological techniques and the development of new experimental techniques. Thus, the resolution of genetic analysis and a number of immunological methods was increased. The cultivation of somatic cells, the isolation of biochemical mutants of microorganisms and somatic cells, etc., were introduced into the practice of research. The experimental method began to be widely enriched with the methods of physics and chemistry, which turned out to be extremely valuable not only as independent methods, but also in combination with biological methods. For example, the structure and genetic role of DNA were elucidated as a result of the combined use of chemical methods for isolating DNA, chemical and physical methods for determining its primary and secondary structure, and biological methods (transformation and genetic analysis of bacteria), proving its role as a genetic material.
At present, the experimental method is characterized by exceptional possibilities in the study of life phenomena. These possibilities are determined by the use of various types of microscopy, including electronic microscopy with the technique of ultrathin sections, biochemical methods, high-resolution genetic analysis, immunological methods, various different methods cultivation and in vivo observation in cell, tissue and organ cultures, labeling of embryos, in vitro fertilization, the method of labeled atoms, X-ray diffraction analysis, ultracentrifugation, spectrophotometry, chromatography, electrophoresis, sequencing, construction of biologically active recombinant DNA molecules, etc. New quality, incorporated in the experimental method, caused qualitative changes in the modeling. Along with modeling at the level of organs, modeling at the molecular and cellular levels is currently being developed.

Modeling method

Modeling is based on such a technique as analogy - this is an inference about the similarity of objects in a certain respect based on their similarity in a number of other respects.

Model is a simplified copy of an object, phenomenon or process, replacing them in certain aspects.

A model is something that is more convenient to work with, that is, something that is easier to see, hear, remember, write down, process, transmit, inherit, and easier to experiment with, compared to the modeling object (prototype, original).
Karkishchenko N.N. Fundamentals of Biomodelling. - M.: VPK, 2005. - 608 p. S. 22.

Modeling - this, respectively, is the creation of a simplified copy of an object, phenomenon or process.

Modeling:

1) creation of simplified copies of objects of knowledge;

2) the study of objects of knowledge on their simplified copies.

Modeling method - this is the study of the properties of a particular object by studying the properties of another object (model), which is more convenient for solving research problems and is in a certain correspondence with the first object.

Modeling (in a broad sense) is the main method of research in all fields of knowledge. Modeling methods are used to assess the characteristics of complex systems and make scientifically based decisions in various areas of human activity. An existing or planned system can be effectively investigated using mathematical models (analytical and simulation) in order to optimize the process of system functioning. The system model is implemented on modern computers, which in this case act as an experimenter's tool with the system model.

Modeling allows you to study any process or phenomenon, as well as directions of evolution by recreating them in the form of a simpler object using modern technologies and equipment.

Modeling theory - the theory of replacing the original object with its model and studying the properties of the object on its model.
Modeling - a research method based on replacing the original object under study with its model and working with it (instead of the object).
Model (original object) (from lat. modus - “measure”, “volume”, “image”) - an auxiliary object that reflects the most essential for the study of the patterns, essence, properties, features of the structure and functioning of the original object.
When people talk about modeling, they usually mean modeling some system.
System - a set of interrelated elements, united to achieve a common goal, isolated from the environment and interacting with it as an integral whole, and at the same time showing the main system properties. 15 main system properties are singled out, which include: emergence (emergence); wholeness; structuredness; integrity; subordination to the goal; hierarchy; infinity; ergaticity; openness; irreversibility; unity of structural stability and instability; nonlinearity; potential multivariance of actual structures; criticality; unpredictability in the critical region.
When modeling systems, two approaches are used: classical (inductive), historically the first, and systemic, which has been developed recently.

Classic approach. Historically, the classical approach to the study of the object, the modeling of the system, was the first to develop. The real object to be modeled is divided into subsystems, initial data (D) for modeling are selected and goals (T) are set, reflecting certain aspects of the modeling process. Based on a separate set of initial data, the goal is to model a separate aspect of the functioning of the system; on the basis of this goal, a certain component (K) of the future model is formed. The set of components is combined into a model.
That. components are summed, each component solves its own tasks and is isolated from other parts of the model. We apply the approach only for simple systems, where it is possible to ignore the relationship between components. Two distinctive aspects of the classical approach can be noted: 1) there is a movement from the particular to the general when creating a model; 2) the created model (system) is formed by summing up its individual components and does not take into account the emergence of a new systemic effect.

Systems approach - a methodological concept based on the desire to build a complete picture of the object under study, taking into account the elements of the object that are important for the problem being solved, the links between them and external links with other objects and the environment. With the complication of modeling objects, it became necessary to observe them from a higher level. In this case, the developer considers this system as some subsystem of a higher rank. For example, if the task is to design an automated control system for an enterprise, then from the standpoint of a systematic approach, we must not forget that this system is an integral part of the automated control system of an association. The system approach is based on the consideration of the system as an integrated whole, and this consideration during development begins with the main thing - the formulation of the goal of functioning. Important for the system approach is the definition of the structure of the system - the totality of links between the elements of the system, reflecting their interaction.

There are structural and functional approaches to studying the structure of a system and its properties.

At structural approach the composition of the selected elements of the system and the links between them are revealed.

At functional approach the algorithms of system behavior are considered (functions - properties that lead to the achievement of the goal).

Modeling types

1. Object Modeling , in which the model reproduces the geometric, physical, dynamic or functional characteristics of the object. For example, bridge model, dam model, wing model
aircraft, etc.
2. Analog simulation , in which the model and the original are described by a single mathematical relation. An example is the electrical models used to study mechanical, hydrodynamic and acoustic phenomena.
3. Iconic modeling , in which schemes, drawings, formulas act as models. The role of sign models has increased especially with the expansion of the use of computers in the construction of sign models.
4. Closely connected with the iconic mental modeling , in which the models acquire a mentally visual character. An example in this case is the model of the atom, proposed at the time by Bohr.
5. Model experiment. Finally, a special type of modeling is the inclusion in the experiment not of the object itself, but of its model, due to which the latter acquires the character of a model experiment. This type of modeling indicates that there is no hard line between the methods of empirical and theoretical knowledge.
Is organically connected with modeling idealization - mental construction of concepts, theories about objects that do not exist and are not feasible in reality, but those for which there is a close prototype or analogue in the real world. Examples of ideal objects constructed by this method are the geometric concepts of a point, line, plane, etc. All sciences operate with this kind of ideal objects - an ideal gas, an absolutely black body, a socio-economic formation, the state, etc.

Modeling methods

1. Full-scale modeling - an experiment on the object under study, which, under specially selected experimental conditions, serves as a model of itself.
2. Physical modeling - an experiment on special installations that preserve the nature of phenomena, but reproduce the phenomena in a quantitatively changed scaled form.
3. Math modeling - the use of models of a physical nature that differ from the simulated objects, but have a similar mathematical description. Full-scale and physical modeling can be combined into one class of physical similarity models, since in both cases the model and the original are the same in physical nature.

Modeling methods can be classified into three main groups: analytical, numerical and simulation.

1. Analytical modeling methods. Analytical methods make it possible to obtain the characteristics of the system as some functions of the parameters of its functioning. Thus, the analytical model is a system of equations, in the solution of which the parameters necessary for calculating the output characteristics of the system (average task processing time, throughput, etc.) are obtained. Analytical methods give exact values ​​of the characteristics of the system, but are used to solve only a narrow class of problems. The reasons for this are as follows. First, due to the complexity of most real systems, their complete mathematical description (model) either does not exist, or analytical methods for solving the created mathematical model have not yet been developed. Secondly, when deriving the formulas on which analytical methods are based, certain assumptions are made that do not always correspond to the real system. In this case, the use of analytical methods has to be abandoned.

2. Numerical modeling methods. Numerical methods involve the transformation of the model to equations, the solution of which is possible by the methods of computational mathematics. The class of problems solved by these methods is much wider. As a result of applying numerical methods, approximate values ​​(estimates) of the output characteristics of the system are obtained with a given accuracy.

3. simulation modeling methods. With the development of computer technology, simulation methods have been widely used to analyze systems in which stochastic influences prevail.
The essence of simulation modeling (IM) is to simulate the process of functioning of the system in time, while observing the same ratios of the duration of operations as in the original system. At the same time, the elementary phenomena that make up the process are imitated, their logical structure, the sequence of flow in time is preserved. As a result of the application of IM, estimates of the output characteristics of the system are obtained, which are necessary when solving problems of analysis, control and design.

In biology, for example, it is possible to build a model of the state of life in a reservoir after some time when one, two or more parameters (temperature, salt concentration, presence of predators, etc.) change. Such techniques became possible due to the penetration into biology of the ideas and principles of cybernetics - the science of control.

The classification of types of modeling can be based on various signs. Depending on the nature of the studied processes in the system, modeling can be divided into deterministic and stochastic; static and dynamic; discrete and continuous.
deterministic Simulation is used to study systems whose behavior can be predicted with absolute certainty. For example, the path traveled by a car during uniformly accelerated movement under ideal conditions; a device for squaring a number, etc. Accordingly, a deterministic process proceeds in these systems, which is adequately described by a deterministic model.

Stochastic (probabilistic) modeling is used to study a system, the state of which depends not only on controlled, but also on uncontrolled influences, or in itself there is a source of randomness. Stochastic systems include all systems that include a person, such as factories, airports, computer systems and networks, shops, consumer services, etc.
static modeling is used to describe systems at any point in time.

dynamic modeling reflects the change in the system over time (the output characteristics of the system at a given point in time are determined by the nature of the input actions in the past and present). An example dynamic systems are biological, economic, social systems; such artificial systems as a plant, an enterprise, a production line, etc.
Discrete simulation is used to study systems in which input and output characteristics are measured or change discretely over time, otherwise continuous simulation is used. For example, an electronic clock, an electric meter are discrete systems; sundial, heating devices - continuous systems.
Depending on the form of representation of an object (system), mental and real modeling can be distinguished.
At real (natural) modeling, the study of the characteristics of the system is carried out on a real object, or on its part. Real simulation is the most adequate, but its capabilities, taking into account the characteristics of real objects, are limited. For example, carrying out a real simulation with an enterprise automated control system requires, firstly, the creation of an automated control system; secondly, conducting experiments with the enterprise, which is impossible. Real simulation includes a production experiment and complex tests, which have a high degree of reliability. Another kind of real simulation is physical. In physical modeling, the study is carried out on installations that preserve the nature of the phenomenon and have a physical similarity.
mental simulation is used to simulate systems that are practically unrealizable on a given time interval. The basis of mental modeling is the creation of an ideal model based on an ideal, mental analogy. There are two types of mental modeling: figurative (visual) and symbolic.
At figuratively modeling on the basis of human ideas about real objects, various visual models are created that display the phenomena and processes occurring in the object. For example, models of gas particles in the kinetic theory of gases in the form of elastic balls acting on each other during a collision.
At iconic modeling describe the simulated system using conventional signs, symbols, in particular, in the form of mathematical, physical and chemical formulas. The most powerful and developed class of sign models are mathematical models.
Mathematical model - this is an artificially created object in the form of mathematical, symbolic formulas that displays and reproduces the structure, properties, relationships and relationships between the elements of the object under study. Further, only mathematical models and, accordingly, mathematical modeling are considered.
Math modeling - a research method based on replacing the original object under study with its mathematical model and working with it (instead of the object) . Mathematical modeling can be divided into analytical (AM) , imitation (MI) , combined (KM) .
At AM an analytical model of the object is created in the form of algebraic, differential, finite-difference equations. The analytical model is investigated either by analytical methods or by numerical methods.
At THEM a simulation model is created, a statistical modeling method is used to implement the simulation model on a computer.
At KM the process of system operation is decomposed into subprocesses. For those of them, where possible, use analytical methods, otherwise - simulation.

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Introduction

Almost all of us are carriers of certain genetic defects, and these defects occur constantly, throughout our lives. Where do they come from? Is it possible to consider the load of genetic defects as a predestination, maybe this load is a consequence of the fall? Is it really the result of heredity or the influence of the environment in which we live?

These questions concern millions of people, because genetic defects become the causes of severe psychophysical diseases that are difficult to treat, and many are generally incurable.

Psychogenetics is a field of knowledge bordering between psychology and genetics, characterizing the relative role and interaction of genetic and environmental factors in the formation of a person's mental individuality. (SSU, p. 8)

The problems of psychogenetics have been and continue to be dealt with by scientists from various branches of science - these are biologists, geneticists, doctors, theologians, and teachers. F. Galton's research laid the foundation for psychogenetics, thanks to the works of G. Siemens, the final design was given to the twin method, which has become one of the main tools of modern psychogenetics. In the two-volume collection of selected works by K.D. Ushinsky there is a special chapter “Heredity of habits and development”, where he recognizes the possibility of inheriting the nervous inclinations of “habits”, which may subsequently, depending on the circumstances, either develop or die out. In 1962, J. Watson, F. Crick and M. Wilkins discovered the structure of DNA, which predetermined almost all subsequent development of biology and genetics. From a theological point of view, Professor Ted Peters paid attention to the problem of genetic determinism, considering as factors of development not only the environment and heredity, but most importantly, the personality itself, which is able to control genes.

The methods available to psychogenetics make it possible to very reliably solve its main task: to elucidate the role that heredity and environmental factors play in the formation of psychological and psychophysiological characteristics, individual trajectories of human development.

In this way, relevance of this topic is due to the need to study the role of heredity and environmental factors in the formation of individual psychophysical characteristics, in order to determine the possibility of successful application of the data obtained not only in medicine, but also in Orthodox pedagogy.

Target of this work is a theoretical review of modern methods for studying human psychogenetics and determining the scope of these studies in Orthodox pedagogy.

Object of study – psychogenetics in a pedagogical context.

Subject of study – modern methods of human psychogenetics.

Realization of the set goal involves the formulation and solution of the following tasks :

1) To trace the development of psychogenetics from its origins to the present;

2) Establish a connection between psychogenetic research and pedagogy;

3) Describe modern ideas about the complex influence of heredity and environment on the process of forming a child's personality;

4) To study and characterize the methods of psychogenetics;

5) Compare existing methodologies and analyze the limitations of each method;

6) To identify areas of application of these studies in Orthodox pedagogy;

Work structure . The study consists of an introduction, two chapters, a conclusion, a list of references, an appendix.

§1.1. Psychogenetics as a scientific discipline.

Stages of development of psychogenetics.

Psychogenetics is an interdisciplinary field of knowledge, borderline between psychology (more precisely, differential psychology) and genetics; the subject of her research is the relative role and interaction of factors of heredity and environment in the formation of individual differences in psychological and psychophysiological characteristics.

Psychogenetics has recently emerged as an independent science. The beginning of its formation is associated with the name of the English scientist F. Galton. In 1865, he published the article "Hereditary Talent and Character", which opened a series of his works on human heredity, including "Hereditary Genius: Its Laws and Consequences" (1869), "The History of Twins as a Criterion of the Relative Strength of Nature and Education" ( 1876). Thus, F. Galton became the founder of the psychology of individual differences and psychometrics. Period from 1865 to 1900 can be defined as the time of the birth of psychogenetics. The next period from 1900 to the end of the 30s. characterized by the development of the methodology of psychogenetics, the formation of psychogenetics as an independent scientific discipline and the accumulation of experimental results. In the 40s. interest in psychogenetics declined, which was associated with the war, the spread of racism, which was covered by genetics, the lack of new ideas in the doctrine of heredity. With the discovery in 1953 of the molecular basis of heredity, the prerequisites for subsequent success in psychological research were created. At this, the third stage - until the 60s. – psychogenetic studies of intelligence, various mental anomalies were carried out. This stage can be defined as the time of accumulation of empirical material. In 1960, the scientific society "Association of Genetics of Behavior" was created and the journal of this society "Genetics of Behavior" began to appear. This year is considered as the beginning of the modern stage in the development of modern psychogenetics.

In the same year when F. Galton published his works, essays by V.M. Florinsky "Improvement and degeneration of the human race" (1865). He considered one of the important means of improving the “human breed” to be the conscious selection of married couples, so that if one of the parents had a pathological symptom, he would oppose the normal symptom of the other parent.

The first study in Russia of the hereditary nature of mental properties belongs to Academician K.F. Wolf, who in the 19th century was engaged in the "theory of freaks", including the transmission of anomalies to offspring. The nature of individual characteristics was also of interest to teachers. In the works of K.D. Ushinsky there is a section called "the heredity of habits and the development of instincts."

Experimental studies were carried out mainly in two scientific centers: in Petrograd - Bureau of Eugenics and in Moscow at the Medical Biological Institute (since 1935 Medical Genetic). In 1937, the Medical Genetic Institute was closed and work in the field of psychogenetics ceased until the 1960s.

Domestic psychogenetic research resumed as part of the study of the nature of interindividual differences in the properties of the nervous system in the laboratory of B.M. Teplova, then V.B. Nebylitsyn. Since 1972, these studies have been continued in the laboratory of I.V. Ravich-Shcherbo at the Research Institute of General and Pedagogical Psychology of the Academy of Pedagogical Sciences of the USSR. In our time, psychogenetic research is carried out in many scientific institutions in our country.

1.2. Significance of psychogenetic research for pedagogy

The uniqueness, the uniqueness of the psychological appearance of each person is one of those obvious phenomena of our psyche, which is most vigorously discussed and studied by various sciences. This is philosophy, and psychology, and genetics, and medicine, and many applied sciences and, of course, pedagogy.

The teacher in his work meets with the fact that people are psychologically different, and seeks to understand the origins of this diversity. This intuitive understanding of the psychological diversity of people and the desire to “guess”, to diagnose individuality are rooted in the deep past. In the treatise "Moral Characters", the author of which was Aristotle's friend and successor Theophrastus, 30 bright characterological types and their specific manifestations are described, here are descriptions a large number informative psychodiagnostic indicators. Since ancient times, there has been physiognomy (from Greek words meaning: “nature”, “natural inclinations” and “knowledgeable”, “insightful”) - the doctrine of recognizing natural individual characteristics, in particular character, according to the physical characteristics of a person, his appearance. In the middle of the XVII century. the Italian physician C. Baldo published the first work on graphology "Discourses on the method of recognizing the customs and qualities of a writer from his letter." The study of characterological types according to physical characteristics, handwriting and other indicators continues even now, it is used to solve a variety of problems, including psychological and pedagogical ones.

In modern pedagogy, there is the concept of a student-centered approach to teaching and upbringing, its implementation implies not only the teacher's knowledge of a person's individuality, but also the possession of methods for diagnosing it. On this basis, the teacher has the opportunity to predict the further development of the personality, as well as to correct and optimize it.

An example of the dependence of the effectiveness of learning on the individual characteristics of the student is the work of the German researcher G. Klaus "Introduction to the differential psychology of learning" [ Klaus G. Introduction to the differential psychology of learning. M., 1987.]. The data of his research suggest that, knowing the dependence of educational success on certain personality characteristics that are not directly related to this activity (i.e., not related, for example, to knowledge and skills in this area), it is possible to optimize human activity, but under one obligatory condition: if the basic individual characteristics are ontogenetically stable.

The data of psychogenetic studies allow the teacher to competently organize work with children. This is especially true of correctional work with students with mental development disorders. It is believed that among children, every tenth child is at risk of an abnormal type of development. This can be criminogenic behavior, episodes of depression or anxiety, as well as a violation of intellectual or emotional development: from a rare form of autism to a specific learning disability, as well as in a state bordering on the clinic and the norm - attention deficit hyperactivity disorder. (SGU, p.13)

It is very important for a teacher to know the features of the manifestation of such diseases, to differentiate them, to master the methods of working with children prone to mental illness. This allows you to do the data of psychogenetics. For example, for a general assessment of a child's developmental delay, an educator can use the definition of an intelligence quotient. The obtained values ​​make it possible to qualify the degree of mental disorder and choose the best ways to solve it. Knowing the characteristics of the intellect, perception and memory of a child with autism, a teacher can productively conduct correctional work.

Thus, the data of psychogenetic studies are a necessary tool in both correctional and educational work of a teacher. They serve as both a theoretical support and a practical basis for identifying certain personality traits, which helps the teacher optimize the educational process.

1.3. Modern ideas about the complex influence of heredity and environment on the process of formation of the child's personality

As already mentioned in the introduction, psychogenetics deals with the problems of the role of heredity and the environment in the formation of the mental and psychophysiological properties of a person. The aim of the research is to try to find out how genetic and environmental factors are involved in the formation of the phenotype. More recently, psychologists believed that the characteristics of human behavior are almost entirely determined by the influences of the environment in which development takes place. The merit of psychogenetics is that it drew the attention of scientists to the nature of individual differences in humans. (Aleksandrov, p. 28)

Psychogenetics has shown that absolutely identical influences can lead not to an increase in similarity, but to the emergence of differences between people. Different genotypes under the influence of the same environmental influences can form different phenotypes. For example, the same environmental influences are experienced differently by family members and can lead to differences for many mental traits. (Aleksandrov, pp. 28-32)

Moreover, a simple separation of genetic and environmental influences is practically impossible in some cases. The genotype can actively interact with the environment, to the extent that the effects of the environment can be predetermined to some extent by the characteristics of the genotype. Often, environmental influences, which are, for example, a risk factor for the occurrence of some pathology, are most pronounced in those individuals who have a genetically determined predisposition. (Alexandrov 28-32)

In the context of the psychogenetic study of environmental characteristics, three points are extremely important.

First, genetic studies consistently point to the critical role of environmental factors in shaping psychological differences between individuals. Numerous psychogenetic works have shown in the clearest way how important the role of genetic factors is in explaining interindividual variability in a variety of traits. In some cases (for example, for the variability (variability) of intelligence indicators), genetic influences explain 50% of phenotypic variability. What, however, explains the remaining 50%? The answer to this question is very simple: for the most part, the environment is responsible for the remaining 50%, or rather, the features of the environment in which carriers of genotypes develop and live.

Secondly, in the context of the genetics of quantitative traits, the concept of environment is defined much more broadly than in psychology. According to this definition, the concept of "environment" includes all types of environmental influences - family-wide, individual and any other (including its physical and physiological components, perinatal conditions, diet, diseases of early childhood, etc.), while in psychology environmental conditions are usually equated only with the socio-economic and psychological conditions of the child's growing up.

Thirdly, psychogenetics focuses on the question of what is (at the moment in a given population), and not on the question of what can happen. For example, the high values ​​of the heritability coefficient obtained in the study of interindividual variability in height states the fact that in given time in a given population, growth variance is explained mainly by genetic differences between members of a given population (which is). However, certain environmental interventions (eg, dietary changes and more vitamins in the diet) can have an impact on the formation of inter-individual differences in the population for such a highly inherited trait as height (which can happen).

In the last 5-10 years, psychogeneticists have discovered three very unexpected phenomena:

a) in children growing up in the same family, the environment forms differences rather than similarities;

b) many psychological tools (questionnaires, observational data, etc.) used to measure environmental characteristics show an unexpectedly high level of genetic control.

c) when the phenotypic dispersion of the overwhelming majority of psychological traits studied by psychogenetics is decomposed, the role of the general family environment turns out to be insignificant.

All this makes it possible to formulate a hypothesis that people create or find certain environmental conditions that correspond to their genotypes, and are not passive "victims" of their genes or the environment "inherited" to them. In other words, the individual genotype turns out to be the "constructor" of the individual environment.

Thus, the study of the genotype is impossible and inadequate without studying the environment in which it is located. The time of opposing "two factors" - genes and environment - is over. Today we know enough to assert without a shadow of doubt: the emerging individuality is not divided into what is in it from the environment, and what is from the genotype. Development is essentially a process of interweaving and interaction of genes and environment, development is their interaction. (Ravich-Scherbo, 122-128)

2.1. general characteristics methods of psychogenetics

Psychogenetics, along with other psychological disciplines, such as differential psychology, studies individual differences between people. So why does psychogenetics need its own methods? The thing is that psychogenetics has a common object of study with these disciplines, but its own specific subject. Native Methods psychogenetics are necessary precisely in order to assess the contribution of genetic and environmental factors to the phenotypic diversity of a particular trait in a population.

Methods of psychogenetics are experimental schemes that are based on comparing people with different numbers of common genes with a parallel analysis of environmental conditions that are important for the formation of the studied traits. For assessing genetic influences, the ideal situation is when genetically identical people were brought up in different environments, and for assessing environmental influences, when genetically unrelated people were brought up in the same environment. Ultimately, studies conducted by psychogenetic methods make it possible to judge such population characteristics as:

The coefficient of heritability, or the proportion of variability
a trait in a population that arises due to variability
genotypes.

The indicator of the general environment, the general environment variance, or
proportion of phenotypic variance arising from
variability of the general environment. Phenotypic variance is an indicator of the deviation of intelligence from the average value in the sample.

An indicator of an individual environment, an individual-environmental variance, or the proportion of phenotypic variance that arises due to the variability of an individual environment.

At present, three main methods are used in psychogenetics - the family method, the method of adopted children and the method of twins. The method of adopted children cannot be applied in our country, since there is a secrecy of adoption guaranteed by law. In psychogenetics, population and genealogical methods are also used, but they have a low resolution. All five listed methods of psychogenetics will be described below. (Pankratova, pp. 5-8)

2.1. population method

The population method is based on a comparison of representatives of different populations. A population means “a set of freely interbreeding individuals of the same species occupying a certain area and having a common gene pool in a number of generations” (Shevchenko, Topornina, Stvolinskaya, Human Genetics. Textbook for universities. 2002, p. 23). The genetic structure of a population is preserved, provided that there is a free, random formation of parental pairs within the population and no marriages are made with representatives of other populations. In psychogenetics, representatives of different races are most often compared - Caucasoid, Negroid and Mongoloid. An important point is that population groups are studied taking into account such factors as natural and climatic, economic, social and other living conditions. (Pankratova, p. 9) Genetic characteristic populations allows you to establish the gene pool of the population, the factors and patterns that determine the preservation of the gene pool or its change in generations. The study of the distribution of mental properties in different populations makes it possible to predict the prevalence of these properties in subsequent generations. The genetic characterization of a population begins with an estimate of the prevalence of the property or trait under study in the population. According to the prevalence of the trait, the frequencies of genes and corresponding genotypes in the population are determined. (SGU, p. 35)

An example of the population method of psychogenetics is the study of the intellectual abilities of high school students in the United States. Among them - 1631 representatives of the Caucasian race and 730 representatives of the Negroid race. It was found that the distributions of the IQ scores of blacks and whites overlapped strongly, and that the difference between the mean IQs of blacks and whites was about 15 units (see Figure 3). To explain these results, a genetic hypothesis has been proposed, according to which the higher average IQ of whites compared to blacks is associated with differences in their gene pools. (Fogel F., Motulski A. Human Genetics. T. 3. M., 1990. With. 137)

The analysis of the results of a population study is as follows: if representatives of different races that are carriers of different gene pools differ significantly from each other in some psychological or psychophysiological characteristics, then the differences between people in these characteristics are associated with genetic factors. Such reasoning is at least controversial, since representatives of different races can differ significantly from each other and due to different environmental conditions. To assess the contribution of genetic factors, it is necessary to compare representatives of different races living in identical environmental conditions, that is, having the same families, education, professional opportunities, etc. But it is unlikely that people living in different cultures have such comparable conditions.

On the other hand, real populations are rarely completely insulated: people move from one population to another and intermarry. For example, the ancestors of modern US blacks were taken out of Africa 300 years (about 10 generations) ago. Scientists have calculated that the flow of genes from the white population to the Negro went at a rate of 3.6% per 1 generation. Thus, in the modern Negro population of the United States, the proportion of genes of African ancestors is 0.694 of total number genes. In other words, African blacks inherited about 30% of their genes from the white population. As a result, differences within a population become wider than differences between populations. (Pankratova, 9-11)

Thus, the population method of psychogenetics is used to determine the genotypes of populations, predict the mental properties of populations in subsequent generations. But this method has a low resolution due to the impossibility of creating identical conditions for different populations and the impossibility of isolating them from each other - all this becomes a limitation of the method and an obstacle in establishing the gene pool of a population.

2.3. genealogical method

The genealogical method (analysis of pedigrees) is based on a comparison of representatives one family over a number of generations. In order to make this comparison more visual, the pedigree is depicted graphically using special symbols (see Figure 4). When compiling genealogists cal tree there are certain rules. So, the symbols of representatives of one generation are located in one line of the pedigree. Generations are numbered in the direction from previous generations to the present and are affixed to the left of the pedigree in Roman numerals. The designations of children in each family are arranged from left to right in the order of birth and are marked with numbers or years of life.

When analyzing a pedigree, the researcher analyzes the manifestation of a trait in a number of generations. If the sign repeats over a number of generations, it is concluded that genetic the nature of individual differences in this trait. For example, when analyzing the genealogy of the Bernoulli family, we see that in a number of generations there are people with mathematical abilities (see Figure 5). For a researcher, such a large number of mathematicians in the family speaks of the genetic nature of mathematical abilities. But if we start to study the biography of the Bernoulli family, we will find a lot environmental factors that influenced the formation of mathematical abilities (for example, a father was a teacher of his sons in mathematics, an uncle involved his nephews in his work in mathematics, the family had a common circle of friends who were mathematicians, etc.). On the other hand, it is not entirely clear how equal the mathematical abilities of different representatives of the Bernoulli family are, since the presence or absence of a feature is assessed, and not the degree of its severity.

Thus, the genealogical method does not allow exactly to answer the question, due to genetic or environmental factors, the studied trait is repeated in a number of generations. But this method allows us to determine type of inheritance various signs (for example, diseases or abnormal features of appearance) and make a forecast for the future. The carrier of the characteristic we are interested in is called proband. In a number of generations, people with a trait (for example, those affected by a given disease) are designated on the family tree. Next, the logic of feature repetition is analyzed and the type of inheritance is established. For example, Figure 6 shows the pedigree of a person with hypertrichosis. Hypertrichosis is the presence of hair on the edge of the ears. As can be seen from the pedigree, this trait is always transmitted to sons and never to daughters, that is, we can talk about a Y-linked type of inheritance. (Pankratova, pp. 11-14)

Thus, genealogical research by itself, without combining with other methods, has a very low resolution and does not allow one to reliably “separate” the genetic and environmental components of the dispersion of a psychological trait. Although, when combined with other methods, such as twin methods, family data allow us to solve questions that cannot be solved without them (for example, to clarify the type of hereditary transmission - additive or dominant), or to control environmental variables (for example, the general and individual environment, the effect twinship). (Ravich-Scherbo, p.162)

The genealogical method can be useful for teachers in the educational process for the competent selection of teaching methods and principles, organizing corrective work with children.

2.4. family method

Some researchers distinguish the family method among the methods of psychogenetics, which involves a comparison of representatives one family which have a different number of genes in common (see Figure 7). Family members (at least two groups of relatives) are compared in pairs: brothers and sisters (siblings), cousins, second cousins, parents and children, grandparents and grandchildren, aunts and nephews, uncles and nephews, etc. All these pairs of relatives according to the number of common genes can be divided into closer (have more common genes) and less close (have fewer common genes) relatives (see Table 1).

The logic of the method is that if, according to the trait being studied, closer relatives (having more common genes) are more similar in comparison with less close relatives (having fewer common genes), then individual differences in this trait are associated with genetic factors.

But the greater similarity of relatives with a greater degree of kinship may also be associated with environmental factors, since closer relatives tend to have more similar living conditions. In order to raise family reliability research, it is necessary to compare samples of less close relatives who do not usually live together. Thus, for example, comparison of first cousin siblings with second cousins ​​will make it possible to more accurately determine the role of the genotype and environment in the formation of individual differences in this trait than a comparison of native siblings with first cousins.

In addition, in a family study, there are problems when comparing representatives different generations(for example, parents and children). These problems are related to the fact that compared relatives are separated by a fairly large age interval. On the one hand, the influence of the genotype on the studied traits may change with age. On the other hand, diagnosing people different ages, you can get inconsistent results. To overcome these difficulties, it is necessary to conduct a survey of representatives of different generations at the same age. This is possible only when conducting a longitudinal study, that is, when re-testing representatives of the younger generation when they reach the age at which the representatives of the older generation were examined. (Pankratova 14-17)

Thus, the family method makes it possible to fairly accurately assess the contribution of heredity and environment to the formation of individual differences. However, the family study itself has a very low resolution, but the integration of several methods at the same time allows us to resolve controversial issues when interpreting the results. (Pankratova, pp. 28-29)

2.5. Foster child method

When using the method of foster children compare reception children with biological parents and with parents adoptive parents. For the study, children are selected who are given as early as possible to be raised in other people's families (preferably in the first days of life). An adopted child shares 50% of their genes with their biological parents, and shares a common environment with their adoptive parents. Thus, if an adopted child is more similar in some psychological or psychophysiological trait to biological parents, then the researcher concludes that individual differences in this trait are more related to genotype. And if the adopted child is more similar to the adoptive parents, then these differences are associated with environment. (Pankratova, p. 17)

The first work done using this method was published in 1924. The results, from the point of view of the author, indicate that the intelligence of adopted children depends more on the social status of biological parents than on adopted ones. However, as noted by R. Plomin and co-authors, this work had a number of defects: only 35% of the 910 children examined were adopted under the age of 5 years; the measurement of mental abilities was carried out on a rather rough (only three-point) scale. The presence of such flaws complicates the meaningful analysis of the study.

After 25 years, in 1949, the first work appeared, made according to the complete scheme of the method. It was followed by others, the largest of which are two modern programs: Texas and Colorado Foster Research Projects.

One of the very interesting and informative variants of the method is the study of the so-called adopted (consolidated) siblings, i.e. several unrelated children adopted by the same family. Considering that such children do not have common genes, their similarity (if it is found) can only be the result of the action of the general family environment.

There are two schemes of this method: full and partial. The first involves combining data obtained on two groups: separated relatives (biological parents and their children given to adoptive parents; separated siblings) and adopted siblings; the second - either one or another group of data. In the first case, as R. Plomin and his co-authors write, there are “genetic” parents (biological parents and their adopted children), “environmental” parents (adoptive parents with their adopted children) and, as a control, an additional group of “genetic plus environmental” parents (usual biological family). Comparison of these three groups allows you to reliably "dilute" the factors that form family resemblance.

Using the method of foster families, it was shown that in an equally good environment, the distribution of IQ scores of adopted children is shifted towards high values ​​if the biological parents had high intelligence, and towards low values ​​if they had reduced intelligence. (Such results prompted a witty remark from one of the psychogeneticists: “It is best to consider that intelligence is 100% dependent on genes and 100% dependent on the environment.”)

Possible limitations of the method are related to several problems. First, how representative of the population is the group of women who gives up children? But it's controllable. For example, in the largest program - the Colorado Study of Adopted Children - all participants (245 biological parents, their adopted children and adopters, as well as 245 control families who had biological and adopted siblings) were representative of the general population in terms of cognitive characteristics, personality traits, family environment , educational and socio-economic status. The authors note that even if the samples deviate from the population distributions for some parameters, this should be taken into account when interpreting the results, but does not give reason to consider the method invalid.

Secondly, a more specific question arises about the selectivity of placement of children in foster families: are there any similarities between natural and adoptive parents in some respects? It is clear that such a similarity will overestimate the correlation in pairs of a child-adoptive parent, if the trait under study is determined by heredity, and in pairs of a child-biological parent, if it is largely determined by the environment. In any case, estimates of the genetic or environmental component of the variability of a given trait will be distorted.

Thirdly, there is the problem of perinatal influences of the maternal organism on the characteristics of the unborn child, which should increase the similarity between the mother and the given child due to intrauterine, but environmental, rather than genetic factors. According to some researchers, by the time of birth, the human fetus already has some experience. If so, then the resemblance of the biological mother to the given child may be of non-genetic origin. As a result, some researchers even consider that the adopted child method is very informative for studying various postnatal environmental influences, but not for solving the genotype-environment problem.

There are also more subtle circumstances that are important for evaluating the method. For example, the possibility of forming subjective legends about natural parents in a situation where a child knows that he is not native in this family. In experimental work, this creates an uncontrollable hindrance, since such a legend can turn out to be a rather serious educational factor.

In our country, it is impossible to use this method, since we have a legally guaranteed secrecy of adoption. This is humane, pedagogically absolutely the right decision, but it means that the researcher has no right to seek information about either adopted children, or, even more so, about their biological parents.

Thus, the current ideas about the limitations and conditions for using the method of adopted children are described, argued, and for the most part can be either controlled or taken into account when interpreting the results obtained. Therefore, it is one of the main methods of modern psychogenetics. (Ravich-Shcherbo, pp. 162-165)

2.6. twin method

The first attempt to use twins to solve the problem of "nature and nurture" belongs, as already mentioned, to F. Galton, who intuitively foresaw what became scientific truth and a serious research method only several decades later. Fascination with twins was a fairly characteristic phenomenon in science late XIX- beginning of XX century. They studied their biology, pathology, origin, etc. We also find twin works in many well-known psychologists of that time: E. Thorndike, S. Merriman, G. Siemens, and others (Ravich-Shcherbo, p. 165)

There are several varieties of the twin method (see table 2). Classical version of the twin method is based on the comparison of two types twins - monozygotic (MZ) and dizygotic (DZ). Monozygotic twins develop from one fertilized egg (from one zygotes), which in the early stages of division gives rise to two organisms (necessarily of the same sex). Thus, MZ twins are the only people on Earth that have the same sets of genes. (100% shared genes). In turn, dizygotic twins develop from two fertilized eggs (from two zygotes). From a genetic point of view, DZ twins are native siblings with an average of 50% common genes. The difference lies only in the simultaneous development and birth of two children of the same or different sex. Note that opposite-sex pairs of DZ twins are included in a psychogenetic study to assess the influence of the sex factor on individual differences.

The twin method is based on two main assumptions. First: assumed equality environmental influences on the development of MZ and DZ twins. If this postulate is violated, the value of heritability and other components of phenotypic dispersion is distorted. Second: missing systematic differences between twins and singleborns. If this postulate is violated, the conclusions of psychogenetic research cannot be extended to the entire population.

When using the classic version of the twin method, two groups are first recruited, consisting of members of the MZ and DZ twin pairs. Then the similarity in pairs of MZ and similarity in pairs of DZ twins are assessed. (intrapair similarity) according to the trait being studied. After that, intra-pair similarity in the group of MZ twins is compared with intra-pair similarity in the group of DZ twins (see Figure 9).

Logics method is as follows. MZ twins share 100% of their genes, DZ twins share an average of 50% of their genes. At the same time, the equality of environmental influences on the development of MZ and DZ twins is postulated. The similarity between members of twin pairs is determined by both genotype and environment. Therefore, if the measure of intra-pair similarity of MZ twins is higher than the measure of intra-pair similarity of DZ, then individual differences in the studied trait are more related to genetic factors.

When conducting a psychogenetic study using the twin method, the question may arise about zygosity twins, because It is not always easy to tell by eye whether twins are monozygotic or dizygotic. Different methods are used to determine the zygosity of twins. methods, starting with an assessment of the external similarity of twins and ending with a biochemical blood test. The most simple

a way to determine zygosity is to compare twins for a number of traits that are hereditarily set and do not change under the influence of the environment. These include - the color of the eyes and hair, the shape of the lips, ears, nose and nostrils, fingerprints, etc. When examining a large sample of twins, parents or other experts are asked to complete a questionnaire about the similarity of the twins' external features and whether other people confuse the twins.

Restrictions of the twin method are associated with possible environmental differences in the perinatal and postnatal development of MZ and DZ twins, as well as twins and singleborns, to which the results of twin studies are transferred.

Differences in perinatal development may occur due to the unequal blood supply of MZ twins compared to DZ twins. This is because MZ twins quite often have one set of amniotic membranes for two, and DZ twins always have separate sets. As a result, the difference in the supply of oxygen and nutrients through the blood leads to a greater difference in the birth weight of MZ twins compared to DZ twins. In turn, the differences in the perinatal development of twins and singleborn children are due to the fact that in the first case, two children are simultaneously provided with oxygen and nutrients, and in the second case, only one. Therefore, in multiple pregnancies, newborns are, on average, physically less developed compared to single-born children.

Environmental conditions in postnatal The development of MZ and DZ twins may also differ. For example, the similarity of DZ twins is often specifically emphasized by parents (children are dressed the same, given similar names, treated similarly), which is less typical for DZ twins. MZ twins are more likely than DZ twins to be together, have the same circle of friends, the same hobbies, etc. This greater similarity of the environment in pairs of MZ twins, compared with pairs of DZ twins, may lead to additional non-genetic similarity of MZ twins, which contradicts the assumption of equality of environments in MZ and DZ pairs. Another example: environmental features can increase the differences between members of both MH and DZ couples (the desire to be different from a co-twin, the distribution of roles in a couple, different relationships between children and parents). Variants of the influence of a specific twin environment on the similarity of both MZ and DZ twins can be very different. In turn, single-born children, unlike MZ and DZ twins, develop outside the specific twin environment, which can have a significant impact on the formation of the psychological characteristics of the child.

Thus, the limitations of the twin method are associated with pre- and postnatal environmental conditions developments that can increase or decrease the similarity between members of twin pairs. If the postulate of equality of environments violated and the general environment contributes differently to the similarity of MZ and DZ twins for the studied trait:

1) may increase or decrease intrapair
similarity of twins - either MZ or DZ, or both types
twins;

2) intra-pair similarity of twins of different types can
change as unidirectional (for example, decreases
similarity in pairs of both MZ and DZ twins), and different
directionally (for example, the similarity in pairs of MOH and
the similarity in pairs of DZ twins decreases).

To overcome these limitations of the method, it is necessary to evaluate the sensitivity studied signs to the features of the twin environment, that is verify the postulate about the equality of the environments of MZ and DZ twins and the postulate about the representativeness of the sample of twins to the sample of single-born children. Thus, it is possible to assess the relationship between birth weight and the further psychological development of the child; to determine whether the features of the MZ twin environment are more similar and whether this affects the level of psychological similarity, for example, in the properties of temperament; check whether there are significant differences in this trait between twins and single-borns, etc.

2.7. Conclusions on the second chapter

Thus, the most accurate assessment of the contribution of heredity and environment to the formation of individual differences allows the family method, the method of adopted children and the method of twins. These methods can be divided into "rigid" and "soft" experimental designs. The foster child method and the separated twin method allow a clear separation of the influence of genetic and environmental factors, while the classical version of the twin method and the family method require additional validation. In the case of the classical twin method, it is necessary to conduct an additional study to verify the postulate about the equality of the environments of the MZ and DZ twins. In the case of the family method, to increase reliability, a comparison is made of distant relatives, who, as a rule, live and are brought up in different environmental conditions.

It is worth noting that the family study itself has a very low resolution. But the inclusion of family data in a study of foster children (comparison of adopted children with natural and half-siblings) or in a study of twins (comparison of MH and DZ twins with parents and siblings) allows us to resolve controversial issues in the interpretation of the results. For example, combining the family method with the twin method helps to understand the type of inheritance (additive or non-additive) and control for environmental variables (general and individual environment, twin effect).

If only one of the methods of psychogenetics is used in the study, it is recommended to compare the obtained data with the results of studies conducted using other methods. This will help to more accurately interpret the results obtained and, ultimately, more accurately understand the nature of individual differences in the studied psychological or psychophysiological characteristics. As an example, Table 4 provides data on intelligence obtained using different methods. From this table, it can be seen that the similarity in intelligence increases monotonously as the genetic similarity of the compared people increases.

"Modern Methods for Researching the Psychophysiology of Memory"

Introduction

Chapter 1

1.1 Microelectrode method

1.2 Electroencephalography (EEG)

1.3 Magnetoencephalography (MEG)

Chapter 2

2.1 Positron emission tomography

2.2 Nuclear magnetic resonance imaging

Conclusion

Sources and literature

Introduction

Memory is a psychophysiological process consisting of remembering, storing and reproducing information.

The founder of psychophysiology is the English physician David Garjli. During the period of the formation of psychophysiology as a science, special attention was paid to the study of the central nervous system and its physiological manifestations. One of important directions(in the study of the central nervous system) is the search for brain structures responsible for memory. None of the physiological functions has had such a close and comprehensive study by biologists, physiologists, psychologists, neurologists, and other sciences. The accumulated clinical and experimental material made it possible to express a number of theories explaining the processes of memory.

1. The theory of associations by contiguity, similarity, contrast.

2. Gestalt psychology.

3. Behavioral theory.

4. Theory of psychoanalysis.

5. Semantic theory.

6. Biochemical theory.

7. Neural theory.

8. Wave theory of units of memory.

The listed theories allow us to trace the direction of scientists' thoughts and the limitations of the research methods used.

The development of technical progress and the introduction of new research methods allow us to rise to a qualitatively new level of research into the secrets of human memory.

The study of memory has not only scientific, but also practical interest: writing school textbooks, training programs, scheduling school classes. The study of the volume of short-term memory, carried out in preschoolers according to the formula CP \u003d 7 + 2, is only from 5 to 9 pictures, numbers, words. By the volume of short-term memory, one can predict the success of learning or a developmental lag. OKP=2+1 is a learning score. When examining preschoolers, it is necessary to reflect in the child's chart: the type of the central nervous system: sanguine, phlegmatic, choleric, melancholic; biorhythmic activity of the central nervous system: "lark", "owl", "dove"; the prevailing type of memory: auditory, auditory-musical, "auditory-motor", or visual, visual-logical.

The collected information makes it possible to develop the child individually, using the type of memory inherent in him, and to lead the group of children smoothly in the cognitive process. For persons with an auditory type of memory, the first phase of slow sleep, lasting 90-100 minutes, can be used to learn foreign languages, medical terms, formulas in physics, chemistry. The biochemical and electrical activity of the brain in this phase of sleep still remains at the level of wakefulness, and auditory information can be assimilated. Young professionals who go on business trips abroad, having an auditory type of memory, can quickly master colloquial speech. Memory reaches its maximum development by the age of 25, remains at a high level until the age of 40-45, then begins to deteriorate. In this regard, there is an age limit for accepting documents for full-time university and subsequent postgraduate education.

Electroencephalographic research methods and complementary tomographic, vascular biochemical methods made it possible to create maps of brain structures involved in storing and reproducing information, to diagnose the causes of memory impairment. The first generation of devices that allow you to see the thin energy shell surrounding the human body - the aura, allow you to observe the emotional manifestations of memories. Reading information from the emotional and mental shells of the aura is not yet available. This secret side of human memory will also be revealed to the future generation of scientists.

Chapter 1

1.1 Microelectrode method

The study of man and the secrets of his memory keeps pace with technological progress. Graphical electrophysiological research methods using microelectrodes have appeared. They got their name because the diameter of their recording surface is about one micron. Microelectrodes are metal and glass. A metal microelectrode is a rod made of a special high-resistance insulated wire with a recording tip. A glass microelectrode with a diameter of about 1 mm is made of special glass - Pyrex, with a thin unsoldered tip filled with an electrolyte solution. Microelectrodes are brought to the studied parts of the brain responsible for memory in animals, and a graphic recording of the impulse activity of neurons is observed.

1.2 Electroencephalography (EEG)

The first highly informative, non-invasive method for studying the central nervous system in humans was electroencephalography.

The scalp in the places where the electrodes are applied is wiped with alcohol, degreased, then a special electrically conductive gel paste is applied.

There are two types of EEG recording: bipolar and monopolar. In a bipolar lead, the potential difference between two active electrodes is recorded. This method is used in the clinic to diagnose the localization of the pathological focus in the brain. In psychophysiology, the method of monopolar assignment is used. One electrode is placed over the studied area of ​​the brain, the other on the earlobe or mastoid process, where electrical processes are minimal and can be taken as zero.

To compare EEG results obtained in laboratories around the world, it was necessary to create a single standard system for applying electrodes, called the "10-20" system. In accordance with this system, psychophysiology is required to make three measurements of the skull of the subject:

1. Longitudinal size of the skull - the distance from the bridge of the nose to the occiput.

2. Transverse size of the skull - the distance between the external auditory canals.

3. Head circumference measured at the same points.

These dimensions are used to draw a grid, at the intersection of which electrodes are applied. The electrodes located along the midline are marked with the index Z; electrode leads from the left half of the head are numbered with odd indices, from the right half of the head they are numbered with even indices.

Leading electrodes in the "10-20" system:

1. frontal (frontal) F 1 ...

2. central C 1 ...

3. parietal (parietal) P 1 ...

4. temporal (temporal) T 1 ...

5. occipital (occipital) O 1 ...

In healthy people in the state of wakefulness in the occipital areas of the brain responsible for visual memory and orientation in space, an alpha rhythm is recorded with a frequency of 8-13 Hz. For the first time this rhythm was registered and described by Hans Berger under the name alpha rhythm. It is very important to note that with atrophy of the optic nerve, long-term or congenital blindness, the alpha rhythm disappears. But in the parietal region responsible for tactile memory, which is well developed in the blind - compensating for loss of vision, a mu rhythm close in frequency to the alpha rhythm appears. In the experiment, we can observe the change of the alpha rhythm to the mu rhythm, the patient is blindfolded and offered to identify familiar objects by touch.

In persons suffering from a disorder of visual memory and orientation in space, wandering and getting lost on the streets of the city, the alpha rhythm is barely traced, due to inhibition in the occipital region. After a course of magnetotherapy on the occipital region, visual orientation in space and alpha rhythm are restored.

In persons with auditory, musical memory, musicians, composers in the left temporal region responsible for this type of memory, a kappa rhythm close in frequency to the alpha rhythm is recorded.

In the subjects, when performing a piece of music from memory, we easily track the change of the alpha rhythm to the kappa rhythm.

The composer Mozart had a phenomenal auditory memory. At the age of 14 he came to Rome, where he heard a work of church music in St. Peter's Basilica. The notes were kept in the greatest secret and constituted the secret of the papal court. Young Mozart, having come home, reproduced the music he heard from memory. Many years later, it was possible to compare Mozart's recording with the original music, as it turned out, there was not a single mistake in Mozart's music.

What is the EEG of dancers, figure skaters overwhelmed with emotions, who perfectly master auditory, visual, motor memory? As soon as the music begins to sound, a betta rhythm appears in all areas of the brain, fluctuations in the range from 14 to 30 Hz.

We observe the beta rhythm during the paradoxical phase of sleep with rapid movements of the eyeballs, colloquial speech. Parents in this situation, alarmed by the violent manifestations of sleep, rush to wake and calm the child, explaining that this is just a dream. We also observe the beta rhythm in the rare pathology of sleepwalking (somnambulism), which requires medical intervention and parental control of the child.

In persons with a verbal-logical, visual-logical type of memory, slowly entering work, able to maintain concentration and attention for a long time without fatigue, a special Gamma rhythm with a frequency of more than 30 Hz is drawn on the EEG.

Drivers, pilots, military, rescuers, doctors, whose work is often associated with significant emotional stress that requires immediate decision-making, register Theta rhythm with a frequency of 4 to 8 Hz.

In a calmly sitting person, a Delta rhythm is recorded on the EEG. In the first phase of non-REM sleep, which lasts 90-100 minutes, biochemical and electrical activity is close to wakefulness, and a person successfully absorbs auditory information. This allowed students with auditory memory to learn foreign languages ​​in a shorter time.

In the daytime, during wakefulness, the Delta rhythm indicates a tumor of the cerebral cortex.

EEG allows you to monitor the activity of various parts of the brain when solving problems, mental arithmetic, performing tasks on the amount of short-term memory, identifying the causes of forgetfulness or progressive memory deterioration.

1.3 Magnetoencephalography (MEG)

Magnetoencephalography was another non-invasive method for studying memory in humans. MEG is recorded using sensors that are highly sensitive to electromagnetic fields. MEG can be represented as profiles of magnetic fields on the surface of the skull, or as a curved line. MEG supplements information about brain activity obtained using EEG.

Chapter 2

2.1 Positron emission tomography

In recent years, positron emission tomography of the brain has been used to study memory. The patient is intravenously injected with one of the isotopes: oxygen - 15, nitrogen - 13, fluorine - 18 or an analogue of glucose - deoxygmonose. In the brain, isotopes emit positrons, which, colliding with electrons, produce a pair of protons. Above the patient's head is a PET camera that captures protons; information from the camera is fed to a computer that gives an image of the site of pain activity in brain slices. Thus, the researcher can layer-by-layer obtain an image of the brain structures involved in the memorization and reproduction of information.

2.2 Nuclear magnetic resonance imaging (NMR)

To study the processes of storing and reproducing information, nuclear magnetic resonance introscopy is used. For research, the patient is placed in a cylindrical tube with a constant magnetic field, 30,000 times greater than that of the earth. The patient's body is affected by radio waves, tissue protons absorb their energy. After turning off the radio waves, the protons give off energy, which is recorded as a magnetic resonance signal. After processing the signal on a computer, an image appears that characterizes the activity of biochemical processes, the rate of blood flow in the tissues. NMR has become the most powerful visual research method in the psychophysiology of human memory.

For the first time, it was noted that when memorizing the information being studied, biochemical activity is manifested in the left hemisphere of the brain, and when remembering and reproducing information, biochemical activity is manifested in the right hemisphere of the brain. When the patient silently recalled episodes of his own life, there was activity in the anterior sections of the cerebral cortex. When recalling historical events, the activity of the posterior sections of the cerebral cortex was manifested. Remembering visual images leads to the activation of the occipital regions, auditory information - to the activation of the temporal auditory areas of the brain.

Thus, it was concluded that remembering reactivates those areas of the brain that were active when remembering. Visual research methods made it possible to create a map of the activated centers of the brain during memorization and reproduction of information.

Conclusion

The study of human psychophysiology, which began in ancient times, has overcome a long research path. In each era, with the introduction of new research methods, some side of human memory was revealed. In our enlightened 21st century, with the introduction of the microelectrode method, EEG, tomography, NMRI, for the first time it was possible to create maps of brain structures involved in memory processes. The use of NMRI made it possible to visually observe that the processes of storing and reproducing information occur in the auditory type of memory in the temporal region, the visual type of memory - in the occipital regions of the brain, the musical and motor type of memory additionally parietal zones are activated, where the tactile and motor memory zones are located.

Psychophysiological research methods have found their practical application in studying the volume of short-term memory in preschoolers, in order to determine the success of a child's education at school, as well as teaching foreign languages ​​to people with an auditory type of memory during a slow sleep phase lasting 90-100 minutes.

The future generation of scientists will have to study and use for practical purposes the information recorded on the emotional and mental shells of the human aura.

Sources and literature

1. Aleksandrov Yu.I. Psychophysiology. Peter, 2007.

2. Bekhtereva N.P. Neurophysiological aspects of mental activity. L.: Nauka, 1971.

3. Danilova N.N. Psychophysiology. Moscow: Aspect-Press, 2002.

4. Kuzin V.S. Psychology. M, 1999.

5. Luria A.R. A small book about a big memory. M.: MGU, 1968.

6. Maklakov A.G. General psychology. Peter, 2005.

7. Stolyarenko L.D. Fundamentals of psychology. Rostov-on-Don: "Phoenix", 2003.

8. Sergeev B.F. Secrets of memory. M, 1974.

Introduction

Almost all of us are carriers of certain genetic defects, and these defects occur constantly, throughout our lives. Where do they come from? Is it possible to consider the load of genetic defects as a predestination, maybe this load is a consequence of the fall? Is it really the result of heredity or the influence of the environment in which we live?

These questions concern millions of people, because genetic defects become the causes of severe psychophysical diseases that are difficult to treat, and many are generally incurable.

Psychogenetics is a field of knowledge bordering between psychology and genetics, characterizing the relative role and interaction of genetic and environmental factors in the formation of a person's mental individuality. (SSU, p. 8)

The problems of psychogenetics have been and continue to be dealt with by scientists from various branches of science - these are biologists, geneticists, doctors, theologians, and teachers. F. Galton's research laid the foundation for psychogenetics, thanks to the works of G. Siemens, the final design was given to the twin method, which has become one of the main tools of modern psychogenetics. In the two-volume collection of selected works by K.D. Ushinsky there is a special chapter “Heredity of habits and development”, where he recognizes the possibility of inheriting the nervous inclinations of “habits”, which may subsequently, depending on the circumstances, either develop or die out. In 1962, J. Watson, F. Crick and M. Wilkins discovered the structure of DNA, which predetermined almost all subsequent development of biology and genetics. From a theological point of view, Professor Ted Peters paid attention to the problem of genetic determinism, considering as factors of development not only the environment and heredity, but most importantly, the personality itself, which is able to control genes.

The methods available to psychogenetics make it possible to very reliably solve its main task: to elucidate the role that heredity and environmental factors play in the formation of psychological and psychophysiological characteristics, individual trajectories of human development.

In this way, relevance of this topic is due to the need to study the role of heredity and environmental factors in the formation of individual psychophysical characteristics, in order to determine the possibility of successful application of the data obtained not only in medicine, but also in Orthodox pedagogy.

Target of this work is a theoretical review of modern methods for studying human psychogenetics and determining the scope of these studies in Orthodox pedagogy.

Object of study – psychogenetics in a pedagogical context.

Subject of study – modern methods of human psychogenetics.

Realization of the set goal involves the formulation and solution of the following tasks :

1) To trace the development of psychogenetics from its origins to the present;

2) Establish a connection between psychogenetic research and pedagogy;

3) Describe modern ideas about the complex influence of heredity and environment on the process of forming a child's personality;

4) To study and characterize the methods of psychogenetics;

5) Compare existing methodologies and analyze the limitations of each method;

6) To identify areas of application of these studies in Orthodox pedagogy;

Work structure . The study consists of an introduction, two chapters, a conclusion, a list of references, an appendix.

§1.1. Psychogenetics as a scientific discipline.

Stages of development of psychogenetics.

Psychogenetics is an interdisciplinary field of knowledge, borderline between psychology (more precisely, differential psychology) and genetics; the subject of her research is the relative role and interaction of factors of heredity and environment in the formation of individual differences in psychological and psychophysiological characteristics.

Psychogenetics has recently emerged as an independent science. The beginning of its formation is associated with the name of the English scientist F. Galton. In 1865, he published the article "Hereditary Talent and Character", which opened a series of his works on human heredity, including "Hereditary Genius: Its Laws and Consequences" (1869), "The History of Twins as a Criterion of the Relative Strength of Nature and Education" ( 1876). Thus, F. Galton became the founder of the psychology of individual differences and psychometrics. Period from 1865 to 1900 can be defined as the time of the birth of psychogenetics. The next period from 1900 to the end of the 30s. characterized by the development of the methodology of psychogenetics, the formation of psychogenetics as an independent scientific discipline and the accumulation of experimental results. In the 40s. interest in psychogenetics declined, which was associated with the war, the spread of racism, which was covered by genetics, the lack of new ideas in the doctrine of heredity. With the discovery in 1953 of the molecular basis of heredity, the prerequisites for subsequent success in psychological research were created. At this, the third stage - until the 60s. – psychogenetic studies of intelligence, various mental anomalies were carried out. This stage can be defined as the time of accumulation of empirical material. In 1960, the scientific society "Association of Genetics of Behavior" was created and the journal of this society "Genetics of Behavior" began to appear. This year is considered as the beginning of the modern stage in the development of modern psychogenetics.

In the same year when F. Galton published his works, essays by V.M. Florinsky "Improvement and degeneration of the human race" (1865). He considered one of the important means of improving the “human breed” to be the conscious selection of married couples, so that if one of the parents had a pathological symptom, he would oppose the normal symptom of the other parent.

The first study in Russia of the hereditary nature of mental properties belongs to Academician K.F. Wolf, who in the 19th century was engaged in the "theory of freaks", including the transmission of anomalies to offspring. The nature of individual characteristics was also of interest to teachers. In the works of K.D. Ushinsky there is a section called "the heredity of habits and the development of instincts."

Experimental studies were carried out mainly in two scientific centers: in Petrograd - Bureau of Eugenics and in Moscow at the Medical Biological Institute (since 1935 Medical Genetic). In 1937, the Medical Genetic Institute was closed and work in the field of psychogenetics ceased until the 1960s.

Domestic psychogenetic research resumed as part of the study of the nature of interindividual differences in the properties of the nervous system in the laboratory of B.M. Teplova, then V.B. Nebylitsyn. Since 1972, these studies have been continued in the laboratory of I.V. Ravich-Shcherbo at the Research Institute of General and Pedagogical Psychology of the Academy of Pedagogical Sciences of the USSR. In our time, psychogenetic research is carried out in many scientific institutions in our country.

1.2. Significance of psychogenetic research for pedagogy

The uniqueness, the uniqueness of the psychological appearance of each person is one of those obvious phenomena of our psyche, which is most vigorously discussed and studied by various sciences. This is philosophy, and psychology, and genetics, and medicine, and many applied sciences and, of course, pedagogy.

The teacher in his work meets with the fact that people are psychologically different, and seeks to understand the origins of this diversity. This intuitive understanding of the psychological diversity of people and the desire to “guess”, to diagnose individuality are rooted in the deep past. The treatise "Moral Characters", authored by Aristotle's friend and successor Theophrastus, describes 30 striking character types and their specific manifestations, it contains descriptions of a large number of informative psychodiagnostic indicators. Since ancient times, there has been physiognomy (from Greek words meaning: “nature”, “natural inclinations” and “knowledgeable”, “insightful”) - the doctrine of recognizing natural individual characteristics, in particular character, by the physical characteristics of a person, his appearance. In the middle of the XVII century. the Italian physician C. Baldo published the first work on graphology "Discourses on the method of recognizing the customs and qualities of a writer from his letter." The study of characterological types according to physical characteristics, handwriting and other indicators continues even now, it is used to solve a variety of problems, including psychological and pedagogical ones.

In modern pedagogy, there is the concept of a student-centered approach to teaching and upbringing, its implementation implies not only the teacher's knowledge of a person's individuality, but also the possession of methods for diagnosing it. On this basis, the teacher has the opportunity to predict the further development of the personality, as well as to correct and optimize it.

An example of the dependence of the effectiveness of learning on the individual characteristics of the student is the work of the German researcher G. Klaus "Introduction to the differential psychology of learning" [ Klaus G. Introduction to the differential psychology of learning. M., 1987.]. The data of his research suggest that, knowing the dependence of educational success on certain personality characteristics that are not directly related to this activity (i.e., not related, for example, to knowledge and skills in this area), it is possible to optimize human activity, but under one obligatory condition: if the basic individual characteristics are ontogenetically stable.

The data of psychogenetic studies allow the teacher to competently organize work with children. This is especially true of correctional work with students with mental development disorders. It is believed that among children, every tenth child is at risk of an abnormal type of development. This can be criminogenic behavior, episodes of depression or anxiety, as well as a violation of intellectual or emotional development: from a rare form of autism to a specific learning disability, as well as in a state bordering on the clinic and the norm - attention deficit hyperactivity disorder. (SGU, p.13)

It is very important for a teacher to know the features of the manifestation of such diseases, to differentiate them, to master the methods of working with children prone to mental illness. This allows you to do the data of psychogenetics. For example, for a general assessment of a child's developmental delay, an educator can use the definition of an intelligence quotient. The obtained values ​​make it possible to qualify the degree of mental disorder and choose the best ways to solve it. Knowing the characteristics of the intellect, perception and memory of a child with autism, a teacher can productively conduct correctional work.

Thus, the data of psychogenetic studies are a necessary tool in both correctional and educational work of a teacher. They serve as both a theoretical support and a practical basis for identifying certain personality traits, which helps the teacher optimize the educational process.

1.3. Modern ideas about the complex influence of heredity and environment on the process of formation of the child's personality

As already mentioned in the introduction, psychogenetics deals with the problems of the role of heredity and the environment in the formation of the mental and psychophysiological properties of a person. The aim of the research is to try to find out how genetic and environmental factors are involved in the formation of the phenotype. More recently, psychologists believed that the characteristics of human behavior are almost entirely determined by the influences of the environment in which development takes place. The merit of psychogenetics is that it drew the attention of scientists to the nature of individual differences in humans. (Aleksandrov, p. 28)

Psychogenetics has shown that absolutely identical influences can lead not to an increase in similarity, but to the emergence of differences between people. Different genotypes under the influence of the same environmental influences can form different phenotypes. For example, the same environmental influences are experienced differently by family members and can lead to differences for many mental traits. (Aleksandrov, pp. 28-32)

Moreover, a simple separation of genetic and environmental influences is practically impossible in some cases. The genotype can actively interact with the environment, to the extent that the effects of the environment can be predetermined to some extent by the characteristics of the genotype. Often, environmental influences, which are, for example, a risk factor for the occurrence of some pathology, are most pronounced in those individuals who have a genetically determined predisposition. (Alexandrov 28-32)

In the context of the psychogenetic study of environmental characteristics, three points are extremely important.

First, genetic studies consistently point to the critical role of environmental factors in shaping psychological differences between individuals. Numerous psychogenetic works have shown in the clearest way how important the role of genetic factors is in explaining interindividual variability in a variety of traits. In some cases (for example, for the variability (variability) of intelligence indicators), genetic influences explain 50% of phenotypic variability. What, however, explains the remaining 50%? The answer to this question is very simple: for the most part, the environment is responsible for the remaining 50%, or rather, the features of the environment in which carriers of genotypes develop and live.

Secondly, in the context of the genetics of quantitative traits, the concept of environment is defined much more broadly than in psychology. According to this definition, the concept of "environment" includes all types of environmental influences - family-wide, individual and any other (including its physical and physiological components, perinatal conditions, diet, diseases of early childhood, etc.), while in psychology environmental conditions are usually equated only with the socio-economic and psychological conditions of the child's growing up.

Thirdly, psychogenetics focuses on the question of what is (at the moment in a given population), and not on the question of what can happen. For example, the high values ​​of the coefficient of heritability obtained in the study of inter-individual variability in height states the fact that at a given time in a given population, the variance in growth is mainly explained by genetic differences between members of this population (which is). However, certain environmental interventions (eg, dietary changes and more vitamins in the diet) can have an impact on the formation of inter-individual differences in the population for such a highly inherited trait as height (which can happen).

In the last 5-10 years, psychogeneticists have discovered three very unexpected phenomena:

a) in children growing up in the same family, the environment forms differences rather than similarities;

b) many psychological tools (questionnaires, observational data, etc.) used to measure environmental characteristics show an unexpectedly high level of genetic control.

c) when the phenotypic dispersion of the overwhelming majority of psychological traits studied by psychogenetics is decomposed, the role of the general family environment turns out to be insignificant.

All this makes it possible to formulate a hypothesis that people create or find certain environmental conditions that correspond to their genotypes, and are not passive "victims" of their genes or the environment "inherited" to them. In other words, the individual genotype turns out to be the "constructor" of the individual environment.

Thus, the study of the genotype is impossible and inadequate without studying the environment in which it is located. The time of opposing "two factors" - genes and environment - is over. Today we know enough to assert without a shadow of doubt: the emerging individuality is not divided into what is in it from the environment, and what is from the genotype. Development is essentially a process of interweaving and interaction of genes and environment, development is their interaction. (Ravich-Scherbo, 122-128)

2.1. General characteristics of the methods of psychogenetics

Psychogenetics, along with other psychological disciplines, such as differential psychology, studies individual differences between people. So why does psychogenetics need its own methods? The thing is that psychogenetics has a common object of study with these disciplines, but its own specific subject. Psychogenetics' own methods are necessary precisely in order to assess the contribution of genetic and environmental factors to the phenotypic diversity of a particular trait in a population.

Methods of psychogenetics are experimental schemes that are based on comparing people with different numbers of common genes with a parallel analysis of environmental conditions that are important for the formation of the studied traits. For assessing genetic influences, the ideal situation is when genetically identical people were brought up in different environments, and for assessing environmental influences, when genetically unrelated people were brought up in the same environment. Ultimately, studies conducted by psychogenetic methods make it possible to judge such population characteristics as:

The coefficient of heritability, or the proportion of variability
a trait in a population that arises due to variability
genotypes.

The indicator of the general environment, the general environment variance, or
proportion of phenotypic variance arising from
variability of the general environment. Phenotypic variance is an indicator of the deviation of intelligence from the average value in the sample.

An indicator of an individual environment, an individual-environmental variance, or the proportion of phenotypic variance that arises due to the variability of an individual environment.

At present, three main methods are used in psychogenetics - the family method, the method of adopted children and the method of twins. The method of adopted children cannot be applied in our country, since there is a secrecy of adoption guaranteed by law. In psychogenetics, population and genealogical methods are also used, but they have a low resolution. All five listed methods of psychogenetics will be described below. (Pankratova, pp. 5-8)

2.1. population method

The population method is based on a comparison of representatives of different populations. A population means “a set of freely interbreeding individuals of the same species occupying a certain area and having a common gene pool in a number of generations” (Shevchenko, Topornina, Stvolinskaya, Human Genetics. Textbook for universities. 2002, p. 23). The genetic structure of a population is preserved, provided that there is a free, random formation of parental pairs within the population and no marriages are made with representatives of other populations. In psychogenetics, representatives of different races are most often compared - Caucasoid, Negroid and Mongoloid. An important point is that population groups are studied taking into account such factors as natural and climatic, economic, social and other living conditions. (Pankratova, p. 9) The genetic characteristics of populations makes it possible to establish the gene pool of a population, the factors and patterns that determine the preservation of the gene pool or its change in generations. The study of the distribution of mental properties in different populations makes it possible to predict the prevalence of these properties in subsequent generations. The genetic characterization of a population begins with an estimate of the prevalence of the property or trait under study in the population. According to the prevalence of the trait, the frequencies of genes and corresponding genotypes in the population are determined. (SGU, p. 35)

An example of the population method of psychogenetics is the study of the intellectual abilities of high school students in the United States. Among them - 1631 representatives of the Caucasian race and 730 representatives of the Negroid race. It was found that the distributions of the IQ scores of blacks and whites overlapped strongly, and that the difference between the mean IQs of blacks and whites was about 15 units (see Figure 3). To explain these results, a genetic hypothesis has been proposed, according to which the higher average IQ of whites compared to blacks is associated with differences in their gene pools. (Fogel F., Motulski A. Human Genetics. T. 3. M., 1990. With. 137)

The analysis of the results of a population study is as follows: if representatives of different races that are carriers of different gene pools differ significantly from each other in some psychological or psychophysiological characteristics, then the differences between people in these characteristics are associated with genetic factors. Such reasoning is at least controversial, since representatives of different races can differ significantly from each other and due to different environmental conditions. To assess the contribution of genetic factors, it is necessary to compare representatives of different races living in identical environmental conditions, that is, having the same families, education, professional opportunities, etc. But it is unlikely that people living in different cultures have such comparable conditions.

On the other hand, real populations are rarely completely insulated: people move from one population to another and intermarry. For example, the ancestors of modern US blacks were taken out of Africa 300 years (about 10 generations) ago. Scientists have calculated that the flow of genes from the white population to the Negro went at a rate of 3.6% per 1 generation. Thus, in the modern Negro population of the United States, the proportion of genes of African ancestors is 0.694 of the total number of genes. In other words, African blacks inherited about 30% of their genes from the white population. As a result, differences within a population become wider than differences between populations. (Pankratova, 9-11)

Thus, the population method of psychogenetics is used to determine the genotypes of populations, predict the mental properties of populations in subsequent generations. But this method has a low resolution due to the impossibility of creating identical conditions for different populations and the impossibility of isolating them from each other - all this becomes a limitation of the method and an obstacle in establishing the gene pool of a population.

2.3. genealogical method

The genealogical method (analysis of pedigrees) is based on a comparison of representatives one family over a number of generations. In order to make this comparison more visual, the pedigree is depicted graphically using special symbols (see Figure 4). When compiling genealogists cal tree there are certain rules. So, the symbols of representatives of one generation are located in one line of the pedigree. Generations are numbered in the direction from previous generations to the present and are affixed to the left of the pedigree in Roman numerals. The designations of children in each family are arranged from left to right in the order of birth and are marked with numbers or years of life.

When analyzing a pedigree, the researcher analyzes the manifestation of a trait in a number of generations. If the sign repeats over a number of generations, it is concluded that genetic the nature of individual differences in this trait. For example, when analyzing the genealogy of the Bernoulli family, we see that in a number of generations there are people with mathematical abilities (see Figure 5). For a researcher, such a large number of mathematicians in the family speaks of the genetic nature of mathematical abilities. But if we start to study the biography of the Bernoulli family, we will find a lot environmental factors that influenced the formation of mathematical abilities (for example, a father was a teacher of his sons in mathematics, an uncle involved his nephews in his work in mathematics, the family had a common circle of friends who were mathematicians, etc.). On the other hand, it is not entirely clear how equal the mathematical abilities of different representatives of the Bernoulli family are, since the presence or absence of a feature is assessed, and not the degree of its severity.

Thus, the genealogical method does not allow exactly to answer the question, due to genetic or environmental factors, the studied trait is repeated in a number of generations. But this method allows us to determine type of inheritance various signs (for example, diseases or abnormal features of appearance) and make a forecast for the future. The carrier of the characteristic we are interested in is called proband. In a number of generations, people with a trait (for example, those affected by a given disease) are designated on the family tree. Next, the logic of feature repetition is analyzed and the type of inheritance is established. For example, Figure 6 shows the pedigree of a person with hypertrichosis. Hypertrichosis is the presence of hair on the edge of the ears. As can be seen from the pedigree, this trait is always transmitted to sons and never to daughters, that is, we can talk about a Y-linked type of inheritance. (Pankratova, pp. 11-14)

Thus, genealogical research by itself, without combining with other methods, has a very low resolution and does not allow one to reliably “separate” the genetic and environmental components of the dispersion of a psychological trait. Although, when combined with other methods, such as twin methods, family data allow us to solve questions that cannot be solved without them (for example, to clarify the type of hereditary transmission - additive or dominant), or to control environmental variables (for example, the general and individual environment, the effect twinship). (Ravich-Scherbo, p.162)

The genealogical method can be useful for teachers in the educational process for the competent selection of teaching methods and principles, organizing corrective work with children.

2.4. family method

Some researchers distinguish the family method among the methods of psychogenetics, which involves a comparison of representatives one family which have a different number of genes in common (see Figure 7). Family members (at least two groups of relatives) are compared in pairs: brothers and sisters (siblings), cousins, second cousins, parents and children, grandparents and grandchildren, aunts and nephews, uncles and nephews, etc. All these pairs of relatives according to the number of common genes can be divided into closer (have more common genes) and less close (have fewer common genes) relatives (see Table 1).

The logic of the method is that if, according to the trait being studied, closer relatives (having more common genes) are more similar in comparison with less close relatives (having fewer common genes), then individual differences in this trait are associated with genetic factors.

But the greater similarity of relatives with a greater degree of kinship may also be associated with environmental factors, since closer relatives tend to have more similar living conditions. In order to raise family reliability research, it is necessary to compare samples of less close relatives who do not usually live together. Thus, for example, comparison of first cousin siblings with second cousins ​​will make it possible to more accurately determine the role of the genotype and environment in the formation of individual differences in this trait than a comparison of native siblings with first cousins.

In addition, in a family study, there are problems when comparing representatives different generations(for example, parents and children). These problems are related to the fact that compared relatives are separated by a fairly large age interval. On the one hand, the influence of the genotype on the studied traits may change with age. On the other hand, when diagnosing people of different ages, you can get incomparable results. To overcome these difficulties, it is necessary to conduct a survey of representatives of different generations at the same age. This is possible only when conducting a longitudinal study, that is, when re-testing representatives of the younger generation when they reach the age at which the representatives of the older generation were examined. (Pankratova 14-17)

Thus, the family method makes it possible to fairly accurately assess the contribution of heredity and environment to the formation of individual differences. However, the family study itself has a very low resolution, but the integration of several methods at the same time allows us to resolve controversial issues when interpreting the results. (Pankratova, pp. 28-29)

2.5. Foster child method

When using the method of foster children compare reception children with biological parents and with parents adoptive parents. For the study, children are selected who are given as early as possible to be raised in other people's families (preferably in the first days of life). An adopted child shares 50% of their genes with their biological parents, and shares a common environment with their adoptive parents. Thus, if an adopted child is more similar in some psychological or psychophysiological trait to biological parents, then the researcher concludes that individual differences in this trait are more related to genotype. And if the adopted child is more similar to the adoptive parents, then these differences are associated with environment. (Pankratova, p. 17)

The first work done using this method was published in 1924. The results, from the point of view of the author, indicate that the intelligence of adopted children depends more on the social status of biological parents than on adopted ones. However, as noted by R. Plomin and co-authors, this work had a number of defects: only 35% of the 910 children examined were adopted under the age of 5 years; the measurement of mental abilities was carried out on a rather rough (only three-point) scale. The presence of such flaws complicates the meaningful analysis of the study.

After 25 years, in 1949, the first work appeared, made according to the complete scheme of the method. It was followed by others, the largest of which are two modern programs: the Texas and Colorado Foster Research Projects.

One of the very interesting and informative variants of the method is the study of the so-called adopted (consolidated) siblings, i.e. several unrelated children adopted by the same family. Considering that such children do not have common genes, their similarity (if it is found) can only be the result of the action of the general family environment.

There are two schemes of this method: full and partial. The first involves combining data obtained on two groups: separated relatives (biological parents and their children given to adoptive parents; separated siblings) and adopted siblings; the second - either one or another group of data. In the first case, as R. Plomin and his co-authors write, there are “genetic” parents (biological parents and their adopted children), “environmental” parents (adoptive parents with their adopted children) and, as a control, an additional group of “genetic plus environmental” parents (usual biological family). Comparison of these three groups allows you to reliably "dilute" the factors that form family resemblance.

Using the method of foster families, it was shown that in an equally good environment, the distribution of IQ scores of adopted children is shifted towards high values ​​if the biological parents had high intelligence, and towards low values ​​if they had reduced intelligence. (Such results prompted a witty remark from one of the psychogeneticists: “It is best to consider that intelligence is 100% dependent on genes and 100% dependent on the environment.”)

Possible limitations of the method are related to several problems. First, how representative of the population is the group of women who gives up children? But it's controllable. For example, in the largest program - the Colorado Study of Adopted Children - all participants (245 biological parents, their adopted children and adopters, as well as 245 control families who had biological and adopted siblings) were representative of the general population in terms of cognitive characteristics, personality traits, family environment , educational and socio-economic status. The authors note that even if the samples deviate from the population distributions for some parameters, this should be taken into account when interpreting the results, but does not give reason to consider the method invalid.

Secondly, a more specific question arises about the selectivity of placement of children in foster families: are there any similarities between natural and adoptive parents in some respects? It is clear that such a similarity will overestimate the correlation in pairs of a child-adoptive parent, if the trait under study is determined by heredity, and in pairs of a child-biological parent, if it is largely determined by the environment. In any case, estimates of the genetic or environmental component of the variability of a given trait will be distorted.

Thirdly, there is the problem of perinatal influences of the maternal organism on the characteristics of the unborn child, which should increase the similarity between the mother and the given child due to intrauterine, but environmental, rather than genetic factors. According to some researchers, by the time of birth, the human fetus already has some experience. If so, then the resemblance of the biological mother to the given child may be of non-genetic origin. As a result, some researchers even consider that the adopted child method is very informative for studying various postnatal environmental influences, but not for solving the genotype-environment problem.

There are also more subtle circumstances that are important for evaluating the method. For example, the possibility of forming subjective legends about natural parents in a situation where a child knows that he is not native in this family. In experimental work, this creates an uncontrollable hindrance, since such a legend can turn out to be a rather serious educational factor.

In our country, it is impossible to use this method, since we have a legally guaranteed secrecy of adoption. This is a humane, pedagogically absolutely correct decision, but it means that the researcher has no right to seek information about either adopted children, or, even more so, about their biological parents.

Thus, the current ideas about the limitations and conditions for using the method of adopted children are described, argued, and for the most part can be either controlled or taken into account when interpreting the results obtained. Therefore, it is one of the main methods of modern psychogenetics. (Ravich-Shcherbo, pp. 162-165)

2.6. twin method

The first attempt to use twins to solve the problem of "nature and nurture" belongs, as already mentioned, to F. Galton, who intuitively foresaw what became scientific truth and a serious research method only several decades later. The fascination with twins was a rather characteristic phenomenon in science in the late 19th and early 20th centuries. They studied their biology, pathology, origin, etc. We also find twin works in many well-known psychologists of that time: E. Thorndike, S. Merriman, G. Siemens, and others (Ravich-Shcherbo, p. 165)

There are several varieties of the twin method (see table 2). Classical version of the twin method is based on the comparison of two types twins - monozygotic (MZ) and dizygotic (DZ). Monozygotic twins develop from one fertilized egg (from one zygotes), which in the early stages of division gives rise to two organisms (necessarily of the same sex). Thus, MZ twins are the only people on Earth that have the same sets of genes. (100% shared genes). In turn, dizygotic twins develop from two fertilized eggs (from two zygotes). From a genetic point of view, DZ twins are native siblings with an average of 50% common genes. The difference lies only in the simultaneous development and birth of two children of the same or different sex. Note that opposite-sex pairs of DZ twins are included in a psychogenetic study to assess the influence of the sex factor on individual differences.

The twin method is based on two main assumptions. First: assumed equality environmental influences on the development of MZ and DZ twins. If this postulate is violated, the value of heritability and other components of phenotypic dispersion is distorted. Second: missing systematic differences between twins and singleborns. If this postulate is violated, the conclusions of psychogenetic research cannot be extended to the entire population.

When using the classic version of the twin method, two groups are first recruited, consisting of members of the MZ and DZ twin pairs. Then the similarity in pairs of MZ and similarity in pairs of DZ twins are assessed. (intrapair similarity) according to the trait being studied. After that, intra-pair similarity in the group of MZ twins is compared with intra-pair similarity in the group of DZ twins (see Figure 9).

Logics method is as follows. MZ twins share 100% of their genes, DZ twins share an average of 50% of their genes. At the same time, the equality of environmental influences on the development of MZ and DZ twins is postulated. The similarity between members of twin pairs is determined by both genotype and environment. Therefore, if the measure of intra-pair similarity of MZ twins is higher than the measure of intra-pair similarity of DZ, then individual differences in the studied trait are more related to genetic factors.

When conducting a psychogenetic study using the twin method, the question may arise about zygosity twins, because It is not always easy to tell by eye whether twins are monozygotic or dizygotic. Different methods are used to determine the zygosity of twins. methods, starting with an assessment of the external similarity of twins and ending with a biochemical blood test. The most simple

a way to determine zygosity is to compare twins for a number of traits that are hereditarily set and do not change under the influence of the environment. These include - the color of the eyes and hair, the shape of the lips, ears, nose and nostrils, fingerprints, etc. When examining a large sample of twins, parents or other experts are asked to complete a questionnaire about the similarity of the twins' external features and whether other people confuse the twins.

Restrictions of the twin method are associated with possible environmental differences in the perinatal and postnatal development of MZ and DZ twins, as well as twins and singleborns, to which the results of twin studies are transferred.

Differences in perinatal development may occur due to the unequal blood supply of MZ twins compared to DZ twins. This is because MZ twins quite often have one set of amniotic membranes for two, and DZ twins always have separate sets. As a result, the difference in the supply of oxygen and nutrients through the blood leads to a greater difference in the birth weight of MZ twins compared to DZ twins. In turn, the differences in the perinatal development of twins and singleborn children are due to the fact that in the first case, two children are simultaneously provided with oxygen and nutrients, and in the second case, only one. Therefore, in multiple pregnancies, newborns are, on average, physically less developed compared to single-born children.

Environmental conditions in postnatal The development of MZ and DZ twins may also differ. For example, the similarity of DZ twins is often specifically emphasized by parents (children are dressed the same, given similar names, treated similarly), which is less typical for DZ twins. MZ twins are more likely than DZ twins to be together, have the same circle of friends, the same hobbies, etc. This greater similarity of the environment in pairs of MZ twins, compared with pairs of DZ twins, may lead to additional non-genetic similarity of MZ twins, which contradicts the assumption of equality of environments in MZ and DZ pairs. Another example: environmental features can increase the differences between members of both MH and DZ couples (the desire to be different from a co-twin, the distribution of roles in a couple, different relationships between children and parents). Variants of the influence of a specific twin environment on the similarity of both MZ and DZ twins can be very different. In turn, single-born children, unlike MZ and DZ twins, develop outside the specific twin environment, which can have a significant impact on the formation of the psychological characteristics of the child.

Thus, the limitations of the twin method are associated with pre- and postnatal environmental conditions developments that can increase or decrease the similarity between members of twin pairs. If the postulate of equality of environments violated and the general environment contributes differently to the similarity of MZ and DZ twins for the studied trait:

1) may increase or decrease intrapair
similarity of twins - either MZ or DZ, or both types
twins;

2) intra-pair similarity of twins of different types can
change as unidirectional (for example, decreases
similarity in pairs of both MZ and DZ twins), and different
directionally (for example, the similarity in pairs of MOH and
the similarity in pairs of DZ twins decreases).

To overcome these limitations of the method, it is necessary to evaluate the sensitivity studied signs to the features of the twin environment, that is verify the postulate about the equality of the environments of MZ and DZ twins and the postulate about the representativeness of the sample of twins to the sample of single-born children. Thus, it is possible to assess the relationship between birth weight and the further psychological development of the child; to determine whether the features of the MZ twin environment are more similar and whether this affects the level of psychological similarity, for example, in the properties of temperament; check whether there are significant differences in this trait between twins and single-borns, etc.

2.7. Conclusions on the second chapter

Thus, the most accurate assessment of the contribution of heredity and environment to the formation of individual differences allows the family method, the method of adopted children and the method of twins. These methods can be divided into "rigid" and "soft" experimental designs. The foster child method and the separated twin method allow a clear separation of the influence of genetic and environmental factors, while the classical version of the twin method and the family method require additional validation. In the case of the classical twin method, it is necessary to conduct an additional study to verify the postulate about the equality of the environments of the MZ and DZ twins. In the case of the family method, to increase reliability, a comparison is made of distant relatives, who, as a rule, live and are brought up in different environmental conditions.

It is worth noting that the family study itself has a very low resolution. But the inclusion of family data in a study of foster children (comparison of adopted children with natural and half-siblings) or in a study of twins (comparison of MH and DZ twins with parents and siblings) allows us to resolve controversial issues in the interpretation of the results. For example, combining the family method with the twin method helps to understand the type of inheritance (additive or non-additive) and control for environmental variables (general and individual environment, twin effect).

If only one of the methods of psychogenetics is used in the study, it is recommended to compare the obtained data with the results of studies conducted using other methods. This will help to more accurately interpret the results obtained and, ultimately, more accurately understand the nature of individual differences in the studied psychological or psychophysiological characteristics. As an example, Table 4 provides data on intelligence obtained using different methods. From this table, it can be seen that the similarity in intelligence increases monotonously as the genetic similarity of the compared people increases.