6 the subject of study of psychogenetics is. Fundamentals and methods of psychogenetics
What connects sciences such as psychology and genetics? The connecting link is psychogenetics. Let's look at the basics of psychogenetics.
Psychogenetics is a science that studies the role of genes and the environment, their influence, the relationship between the traits that we inherited from our ancestors and the traits that we acquired ourselves.
The emergence of a new branch of science
The history of psychogenetics began in England. The founder of psychogenetics is an English scientist. As the founder of psychogenetics, Galton was the first to conduct research in the field of personality. He managed to collect a huge amount of material, he created measurement procedures and analyses.
Galton was the first to pose the question for the entire scientific community: “How, through what means do individual characteristics appear?” He was the first to try to solve it.
His thoughts interested other scientists, who also began to conduct research and analyze the people around them. What were their results and conclusions?
That is, each of us has our own life path, which has already been laid and paved by heredity, regardless of our conscious reactions. Our direction vector influences:
- Success.
- Behavior.
- Health.
Setting goals
What challenges do scientists face? What does psychogenetics conceal? The main and main task of psychogenetics is to track and identify causes, both genetic and those that arose due to the influence of the surrounding world, as a result of which differences in people are formed.
Thus, the subject of psychogenetics research is nothing more than a person’s character, which is formed through the influence of the external environment and heredity. This is the main subject of psychogenetics.
Individual differences are also the subject of psychogenetics. Scientists are especially interested in the differences between people in a single family; they compare not different races, but rather people in whose veins the same blood flows.
Definition of types of studies
It's time to talk about such a topic as psychogenetics methods. Psychogenetics, as a developed branch of genetics and psychology, has developed its own methods with which it identifies differences between people:
Scientists also conduct research analyzing and comparing people who are hereditarily identical, but grew up in different environments. However, using one type of study does not provide a complete analysis.
2. Genealogical method. Let's get the family tree. Just for fun, you yourself can trace the distinctive features among your family members by comparing the appearance of representatives of different generations using photographs.
However, it is more widely used in medical genetics and anthropology, but in psychogenetics as a separate tool it will provide an incomplete answer. Why? Because the adoption of psychological traits may be due to social continuity, and not just genetics.
3. Population method. The method is based on the study of the continuity of a separate group of genes. A psychogenetics method that can be used to identify any family pathologies.
5. Method of adopted children. Comparison of a child with two families. The characteristic we are interested in is taken and correlated with real parents and adopted ones.
After all types of research, the results are carefully processed.
- Study of the causes of human origin. How do those features that distinguish us from each other arise?
- An accurate definition of human structure. What is it made of and what mechanisms does it consist of?
- Measuring and determining the location of individual characteristics in the character and temperament of a person.
- Identification of certain external factors that influence an individual.
- Patterns of individual personality development, as well as the state of genotype-environmental interactions.
In our time
A popular and much more thoroughly studied issue is the genotype-environmental relationship in changing the level of development, that is, human intelligence. Most of the work is related to the study of the influence on the formation of character and temperament due to certain factors. The human motor sphere fades into the background here.
Now two new branches have appeared in psychogenetics:
- Genetic psychophysiology. This field investigates both environmental and genetic determinants of brain activity.
- Genetics of individual development. Here, research is conducted to determine the role of environment and heredity in the continuity of stages of individual development of the human personality.
Thanks to research in this direction, we can conclude that initially the genome already contains a primary individuality, which subsequently develops and manifests itself in a child and an adult. But the meaning of this conclusion should be correctly understood.
In addition, if different factors are taken into account in the measurement of a psychological trait, then the “genetically given” will not necessarily be unchanged.
Thanks to active research, psychogenetics can identify more and more new environments in which personality development occurs, and psychogenetic research is carried out directly in them:
- Family environment. An environment that is the same for all family members and alien to other families.
- Individual environment. All family members have their own personal environment, and it does not coincide with them.
So, psychogenetics is a modern, actively developing branch of science that studies how we relate to each other within an individual family. How are we different from each other? What influences the differences between people who have the same blood flowing in their veins? This is what psychogenetics is trying to understand - a very interesting and fascinating field. Author: Vera Ivanova
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Psychogenetics test questions
1. Subject and tasks of psychogenetics.
2. History of the development of psychogenetics.
3. Variability. Definition of the concept.
4. Basic concepts of the theory of heredity.
5. Inheritance. Definition of the concept.
6. Genotype and phenotype.
7. Genotype, gene, allele.
8. Dominance. Definition of the concept.
9. Recessiveness. Definition of the concept.
10. Chromosomes. Karyotype.
11. Chromosomal aberrations.
12. The role of G. Mendel in the development of genetics.
13. Mendel's first law.
14. Mendel's second law.
15. Mendel's third law.
16. Non-Mendelian genetics.
17. DNA as the basis of heredity.
18. Structure of DNA.
19. Transcription. Definition of the concept.
20. Broadcast. Definition of the concept.
21. Types and structure of genes.
22. DNA mutations.
23. Natural selection.
24. Methods of psychogenetic research.
25. Geneological method.
26. Method of adopted children.
27. Twin method.
28. A variation of the twin method.
29. Psychogenetic studies of intelligence.
30. Verbal and non-verbal intelligence.
31. Temperament. Definition of the concept.
32. Psychogenetic studies of movement.
33. Motor tests.
34. Genetic psychophysiology. Subject of discipline and tasks.
35. Levels of analysis of brain genetics.
36. Electroencephalography as a research method.
37. Types of electroencephalography and their hereditary conditions.
38. Functional asymmetry. Definition of the concept.
39. The role of heredity and environment in the formation of functional asymmetry.
40. Development of functional asymmetry in ontogenesis.
41. Normative and individual in the development of psychological characteristics.
42. Stability of psychological traits in ontogenesis.
43. Age aspects of psychogenetics.
44. Age aspects of genetic psychophysiology.
45. Mental dysontogenesis.
46. Autism.
47. Features of functional asymmetries in twins.
48. Genotype - environmental relationships in individual development.
49. Concepts, methods and models of age-related psychogenetics.
50. Age dynamics of genetic and environmental determinants.
Psychogenetics
Psychogenetics is an interdisciplinary field of knowledge, borderline "between psychology (more precisely, differential psychology) and genetics; the subject of its research is the relative role and effect of hereditary and environmental factors in the formation of differences in psychological and psychophysiological characteristics. In recent years, the scope of psychogenetic research has included individual development: both mechanisms of transition from stage to stage, and individual development trajectories.
In Western literature, the term “behavioral genetics” is usually used to refer to this scientific discipline. However, in Russian terminology it seems inadequate (at least in relation to humans). And that's why.
In Russian psychology, the understanding of the term “behavior” has changed, and quite dramatically. At L.S. Vygotsky’s “development of behavior” is actually a synonym for “mental development”, and, therefore, the laws established for specific mental functions are valid for it. However, in subsequent years, “behavior” began to be understood more narrowly, rather as a designation of certain external forms, external manifestations of human activity that have personal and social motivation.
S.L. Rubinstein wrote back in 1946 that it is precisely when Motivation moves from the sphere of things, objects, to the sphere of personal-social relations and acquires leading importance in human actions, “human activity acquires a new specific aspect. It becomes behavior in the special sense that this word has when they talk about human behavior in Russian. It is fundamentally different from “behavior” as a term in behavioral psychology, which is retained in this meaning in animal psychology. Human behavior contains as a defining moment the attitude towards moral norms.”
B.G. Ananiev considered the question of the relationship between “behavior” and “activity” in a different aspect, namely from the point of view of which of these two concepts is more general, generic. He believed that his decision could vary depending on the perspective from which he studied the person.
The task of psychogenetics- elucidation of not only hereditary, but also environmental reasons for the formation of differences between people according to psychological characteristics. The results of modern psychogenetic research provide information about the mechanisms of action of the environment to the same, if not greater, extent as about the mechanisms of action of the Genotype. In general terms, it can be argued that the main role in the formation of interindividual variability in psychological characteristics belongs to the individual (unique) environment. Its role is especially high for personality and psychopathological traits. Increasing emphasis in psychogenetic research is being placed on the relationship between family socioeconomic level or length of schooling with the results of children's intelligence tests. And even such formal characteristics as the parameters of the family configuration (number of children, birth order, interval between births) turn out to be important for the individualization of the child - both in the cognitive and personal spheres.
As a result, the similarity of members of a nuclear family in terms of psychological characteristics stated in the study may have both genetic and environmental origins. The same can be said about the decrease in similarity with a decrease in the degree of relatedness: as a rule, in this case we are dealing with different families, i.e. We are talking about a decrease not only in the number of common genes, but also in different family environments. This means that a decrease in similarity in pairs of people related more distantly is also not evidence of the genetic determination of the trait under study: in such pairs the genetic commonality is lower, but at the same time the environmental differences are higher.
All this leads to the conclusion that family research by itself, without combining it with other methods, has a very low resolution and does not allow one to reliably “separate” the genetic and environmental components of the variance of a psychological trait. Although, when combined with other methods, for example with twins, family data makes it possible to solve questions that are impossible to solve without them (for example, to clarify the type of hereditary transmission - additive or dominant), or to control environmental variables (for example, the general family and individual environment, twinning effect).
Methods of psychogenetics
METHODS OF PSYCHOGENETICS (from the Greek psyche - soul, genos - origin) - methods that allow us to determine the influence of hereditary factors and the environment on the formation of certain mental characteristics of a person.
The most informative is twin method. It is based on the fact that monozygotic (identical) twins have an identical genotype, dizygotic (fraternal) twins have a non-identical genotype; Moreover, members of twin pairs of any type must have a similar upbringing environment. Then the greater intrapair similarity of monozygotic twins compared to dizygotic twins may indicate the presence of hereditary influences on the variability of the trait being studied. A significant limitation of this method is that the similarity of the actual psychological characteristics of monozygotic twins may also have a non-genetic origin.
Genealogical method-- study of similarities between relatives in different generations. This requires accurate knowledge of a number of characteristics of direct relatives on the maternal and paternal lines and coverage of the widest possible range of blood relatives; It is also possible to use data from a sufficient number of different families to reveal similarities in pedigrees. This method is mainly used in medical genetics and anthropology. However, the similarity of generations in terms of psychological characteristics can be explained not only by their genetic transmission, but also by social continuity.
Population method allows you to study the distribution of individual genes or chromosomal abnormalities in human populations. To analyze the genetic structure of a population, it is necessary to examine a large group of individuals, which must be representative, that is, representative, allowing one to judge the population as a whole. This method is also more informative when studying various forms of hereditary pathology. As for the analysis of the heritability of normal psychological traits, this method, taken in isolation from other methods of psychogenetics, does not provide reliable information, because differences between populations in the distribution of a particular psychological trait can be caused by social reasons, customs, etc.
Adopted children method- comparison of similarities on some psychological basis between the child and his biological parents, on the one hand, the child and the adoptive parents who raised him, on the other.
The methods require mandatory statistical processing specific to each method. The most informative methods of mathematical analysis require the simultaneous use of at least the first two methods.
The concepts of genotype and phenotype - very important in biology. The totality of all the genes of an organism constitutes its genotype. The totality of all the characteristics of an organism (morphological, anatomical, functional, etc.) constitutes a phenotype. Throughout the life of an organism, its phenotype may change, but the genotype remains unchanged. This is explained by the fact that the phenotype is formed under the influence of the genotype and environmental conditions.
The word genotype has two meanings. In a broad sense, it is the totality of all the genes of a given organism. But in relation to experiments of the type that Mendel performed, the word genotype refers to the combination of alleles that control a given trait (for example, organisms can have the genotype AA, Aa or aa).
The term "genotype" was introduced into science by Johannson in 1909.
(from the Greek phaino - I reveal, reveal and typos - imprint, form, sample) - result the interaction of all the genes of an organism with each other and various environmental factors, a set of characteristics inherent in a given organism.
The term "phenotype" like genotype, it is used in two senses. In a broad sense, it is the totality of all the characteristics of an organism. But in relation to monohybrid crossing, the word phenotype usually denotes the trait that is studied in this crossing, for example, a tall plant has one phenotype, and a dwarf plant has another.
The genotype is the totality of all the genes of a given organism; a phenotype is the totality of all the characteristics of an organism.
It is known that with the same phenotype, organisms can have different genotypes. For example, in Mendel's experiments, plants whose genotype contained AA alleles and plants whose genotype contained Aa alleles did not differ from each other in phenotype. Could there be the opposite situation, when the genotypes of organisms are the same, but the phenotypes are different? In particular, to what extent is the phenotype determined by the genotype, and to what extent by environmental influences? This issue is often discussed at the everyday level in relation to the character or behavior of people. There are two points of view.
According to one of them, a person’s characteristics are entirely determined by his genotype. Behavior is determined by heredity, with which nothing can be done. According to another point of view, heredity in human behavior plays a minor role in comparison with living conditions and, especially, upbringing.
Let's consider the influence of heredity and environment on simpler traits than human behavior. Even for such signs, different options are possible.
Some traits are completely determined by the genotype and do not depend on environmental conditions. These include, for example, blood groups and many genetic diseases.
Other traits depend on both the genotype and the environment. For example, a person's height depends on his genotype (remember Galton's work). At the same time, growth also depends on environmental conditions, in particular on nutrition during the growth period. Skin color is largely determined by genotype. But the skin color of people with the same genotype very much depends on the time they spend in the sun (Fig. 122).
Let us consider several typical examples of the influence of the environment on the expression of genes.
1. Even at the earliest period of development of genetics, it was discovered that a trait can be dominant or recessive depending on the conditions in which the organism develops. In 1915, Morgan showed on Drosophila that when grown in dry air, the distribution of stripes on the abdomen of the Drosophila, which is normal for the “wild” type, dominates over the abnormal one, and, on the contrary, when there is excess humidity, the abnormal distribution of stripes dominates. Observations of this kind once again showed the differences between genotype and phenotype: with the same genotype, the phenotype depended on external conditions.
2. The influence of the external environment on phenotype can be demonstrated using the example of social insects. In bees and ants, males develop from unfertilized eggs, and females from fertilized eggs. However, the phenotype of these females depends on developmental conditions: under some conditions, a fertile female develops, and under others, an infertile worker bee develops. Ants have different “castes” of sterile individuals. The main part of the anthill population is made up of worker ants, who build the anthill, get food, feed the larvae and do all sorts of other work. Many species of ants have “soldiers” - ants with a large head, protected by thick chitin, and with especially powerful jaws. Worker ants and soldiers are underdeveloped females and are sterile. Why do some eggs laid by a female produce working individuals, others - soldiers, and others - winged sexual individuals: males and females? Back in 1910, ant researcher Wassman removed a female from a nest. It turned out that after this the worker ants begin to lay eggs! This experiment showed that the presence of a female inhibits the laying of eggs by working individuals. Upon further study, it turned out that in addition to substances that inhibit the development of new females, substances circulate in the anthill that, on the contrary, stimulate the development of ovaries in workers and larvae. These substances are produced by special glands of worker ants. Under normal conditions, worker ants feed these substances to the queen and larvae, from which males and females develop. If there is no queen in the anthill, these substances are mainly received by the larvae. If there are few larvae, then the worker ants feed each other with these substances and then begin to lay eggs. Thus, it was found that the development of the larvae depends on what food they receive from working ants and what additives are in the food. In the same way, in bees, the nature of the food and additives determines whether the larva will develop into a worker bee or into a queen bee.
3. Ermine rabbits have white fur, but certain parts of the body - paws, ears, tip of the muzzle and tail - are black. If you cut off an area on a rabbit's back, which is covered with white fur, and keep the rabbit at a low temperature, black hair will grow on this area. Of course, such black spots in an unusual place are not inherited by the descendants of this rabbit.
The above examples show that in reality, in many cases, it is not the trait as such that is inherited, but the ability to develop a given trait under appropriate environmental conditions, which is passed on from generation to generation.
Let's look again at the concept of a clean line. Groups of animals and plants, the descendants of which over a number of generations do not change in appearance and do not split, are called pure lines (sometimes this concept is applied only to the offspring of self-pollinators). Now we can supplement the definition: organisms belonging to a pure line are homozygous for the alleles that determine the characteristics being studied.
The Danish geneticist Johannsen conducted experiments to determine the possibility of selection in pure lines. He saw that this plant, a pea, belonging to a pure line, had peas of different sizes: small, medium and large. Johannsen planted the smallest peas and the largest and received offspring from them. From plants grown from the smallest peas, the smallest ones were taken again, and from plants grown from large peas, the largest ones were taken. After such a procedure, carried out for a number of generations, it turned out that the ratio of peas of different sizes (small, medium and large) was the same in the selected plants grown from the smallest seeds and those grown from the largest seeds; however, it did not differ from the ratio that was in the original parent plant. The size of the peas was determined by various random reasons (some formed when there was more sun, others when there was more moisture, etc.). But the genotype of all plants was the same and selection could not change the ratio of pea size. This showed that it is inappropriate for breeders to select among the descendants of pure lines. The scatter in the sizes of peas, which arose under the influence of random reasons, was subject to a certain pattern. Most of them were peas of some medium size. There were fewer especially small and especially large peas. The size distribution of peas is one example of a normal distribution.
Let us now return to human behavior. This raises important questions that have long been controversial. For example, is a person born smart or stupid? Are there born criminals? Or intelligence is the result of a good upbringing, and crime is the result of a bad one. However, the answers to these questions are very difficult. First, it is difficult to measure a person's intelligence level and behavioral characteristics. Second, it is difficult to figure out which genes are related to behavior and how people differ in those genes. Thirdly, it is difficult to compare or equalize the conditions of education of different people.
Nevertheless, some research results on this problem deserve attention, for example, those obtained in studies of the inheritance of intelligence. A number of tests have been developed to determine the level of intelligence. Application of these tests to close relatives who were raised together or separately, and to unrelated people who were raised together or separately, showed the following. First, the closer people are related, the closer their intelligence levels are, even if they are raised separately. Identical twins are especially similar to each other (The idea of using twins for genetic research was proposed by F. Galton). This means that genotype plays a significant role in determining intelligence. Second, non-relatives raised together have more similar intelligence scores than similar non-relatives raised apart. This shows that the environment (upbringing) partly determines the level of intelligence. For most people, the influence of heredity and environment are comparable.
Modification variability- these are evolutionarily fixed reactions of the body to changes in environmental conditions with an unchanged genotype. This type of variability has two main features. First, the changes affect most or all individuals in the population and occur in the same way in all of them. Secondly, these changes are usually adaptive in nature. As a rule, modification changes are not passed on to the next generation. A classic example of modification variability is provided by the arrowhead plant, in which the above-water leaves acquire an arrow-shaped shape, and the underwater leaves become ribbon-shaped.
If you remove the white fur from a Himalayan rabbit's back and place it in the cold, black fur will grow in that area. If the black fur is removed and a warm bandage is applied, white fur will grow back. When a Himalayan rabbit is raised at a temperature of 30*C, all its fur will be white. The offspring of two such white rabbits, raised under normal conditions, will have a “Himalayan” coloration. Such variability of characteristics, caused by the action of the external environment and not inherited, is called modification. Examples of modification variability are shown in Fig. 12 .
Usually, when talking about modification changes, they mean morphological changes (for example, changes in leaf shape) or changes in color (some examples are given in paragraph. Influence of the genotype and environment on the phenotype). However, physiological reactions are often included in this group. Regulation of the lactose operon genes in Escherichia coli is an example of such a physiological response. Let us remind you what it consists of. In the absence of glucose in the bacterial environment and in the presence of lactose, the bacterium begins to synthesize enzymes to process this sugar. If glucose appears in the medium, these enzymes disappear and the bacterium returns to standard metabolism.
Another example of a physiological reaction is an increase in the number of red blood cells in the blood of a person who has climbed mountains. When a person goes down, where the oxygen level is normal, the number of red blood cells returns to normal.
In both examples, modification changes have a clearly defined adaptive nature, which is why they are often called physiological adaptations.
Most modifications are not inherited. However, long-term modification changes are also known that persist in the next generation (sometimes even in several generations). What could be their mechanism? How can changes that are caused by the influence of the external environment and are not associated with changes in the genotype persist over several generations?
Let's consider one of the possible options for the mechanism of such a long-term modification. Let us remember that in bacterial operons, in addition to structural genes, there are special sections - a promoter and an operator. An operator is a section of DNA that is located between the promoter and structural genes. The operator may be associated with a special protein - a repressor, which prevents RNA polymerase from moving along the DNA chain and prevents the synthesis of enzymes. Thus, genes can be turned on and off depending on the presence of corresponding repressor proteins in the cell. Let us imagine two such operons, in which one of the structural genes of the first operon encodes a repressor protein for the second operon, and one of the structural genes of the second operon encodes a repressor protein for the first operon (Fig. 123). If the first operon is turned on, the second one is blocked, and vice versa. This two-state device is called a flip-flop. Let's imagine that some environmental influences switched the trigger from the first state to the second. Then this condition can be inherited. The egg will contain repressor proteins that prevent the trigger from switching. However, when environmental conditions change, or some substances enter the cell that remove the repressor protein, the trigger will switch from the second state to the first.
This mechanism of long-term modification is not invented; it exists, for example, in some phages. If phages enter a cell where there are few nutrients for them, they are in one state - they do not multiply, but are only transmitted when the cell divides into daughter cells. If favorable conditions arise in the cell, phages begin to multiply, destroy the host cell and exit it into the environment. The switching of phages from one state to another is carried out using a molecular trigger.
Modifying variability does not affect the hereditary basis of the organism - the genotype and therefore is not transmitted from parents to offspring.
Another feature of modification variability is its group nature. A certain environmental factor causes a similar change in characteristics in all individuals of a given species, breed or variety: under the influence of ultraviolet rays, all people tan, all white cabbage plants in hot countries do not form a head of cabbage. Moreover, unlike mutations, modifications are directed, have adaptive significance, occur naturally, and can be predicted. If the leaves on the trees have already blossomed, and there was frost at night, then in the morning the leaves on the trees will take on a reddish tint. If mice that lived on the plains near the mountains are moved to the mountains, their hemoglobin content in the blood will increase.
Thanks to the occurrence of modifications, individuals directly (adequately) react to changing environmental conditions and better adapt to it, which makes it possible to survive and leave offspring.
In prokaryotes
Modification is the result of the plasticity of cellular metabolism, leading to the phenotypic manifestation of “silent” genes under specific conditions. Thus, modification changes take place within the framework of an unchanged cellular genotype.
There are several types of modification changes. The best known are adaptive modifications, i.e. non-hereditary changes that are beneficial to the body and contribute to its survival in changed conditions. The reasons for adaptive modifications lie in the mechanisms of regulation of gene action. An adaptive modification is the adaptation of E. coli cells to lactose as a new substrate. A number of bacteria have revealed a universal adaptive response in response to various stress influences (high and low temperatures, sharp pH shifts, etc.), manifested in the intensive synthesis of a small group of similar proteins. Such proteins are called heat shock proteins, and the phenomenon itself is called heat shock syndrome. A stressful effect on a bacterial cell causes inhibition of the synthesis of normal proteins, but induces the synthesis of a small group of proteins, the function of which is presumably to counteract the effects of stress by protecting the most important cellular structures, primarily the nucleoid and membranes. The regulatory mechanisms that are triggered in the cell under influences that cause heat shock syndrome are not yet clear, but it is obvious that this is a universal mechanism of nonspecific adaptive modifications.
Not all modifications are necessarily adaptive. With the intensive action of many agents, non-heritable changes are observed, random in relation to the effect that caused them. They appear only in the conditions that cause them. The reasons for the appearance of such phenotypically altered cells are associated with errors in the translation process caused by these agents.
Thus, modification variability does not affect the genetic constitution of the organism, i.e. is not hereditary. At the same time, it makes a certain contribution to the process of evolution. Adaptive modifications expand an organism's ability to survive and reproduce in a wider range of environmental conditions. The hereditary changes that arise under these conditions are picked up by natural selection and in this way a more active development of new ecological niches occurs and a more effective adaptability to them is achieved.
Complete information about the concept of Dominance
According to the generally accepted definition, Dominance (see House), dominance, a form of relationship between paired (allelic) hereditary inclinations - genes, in which one of them suppresses the action of the other. The first is called the dominant allele and is designated by a capital letter (for example, A), the second - recessive allele and is denoted by a lowercase (a). Concept (see Concept) "D." introduced into genetics by G. Mendel. A distinction is made between complete D. and intermediate (semi-dominance). In complete D., the effect of only the dominant allele is manifested; in intermediate D., the effect of both dominant and recessive alleles is manifested with varying degrees of severity (expressiveness). Complete D., like complete recessiveness, is a rare phenomenon. The manifestation of any trait in the phenotype depends on the genotype, i.e., on the action of many genes. Depending on environmental conditions and the composition of genes in the population (and, consequently, on the genotype of the individual), the allele can be dominant, recessive, or manifest itself in intermediate forms. D., according to the English scientist R. Fisher, evolves as a system in which the selection of modifier genes for a given, initially semi-dominant allele occurs. If the initial effect of an allele is unfavorable, then during selection it passes into a latent (recessive) state, but if its effect is positive, into a dominant state. The action (see Day) of such a system can explain the change in the D. allele when it is transferred to another genotype or under the influence of external conditions (when the action of modifier genes can change). English biologists J. B. S. Haldane and S. Wright suggest that those alleles that give an optimal physiological effect, for example, synthesize a certain amount of the corresponding enzyme, are picked up by selection and fixed as dominant. D. is important in medicine and agriculture. In the case of complete dominance, an individual may carry harmful alleles in a recessive state, which will manifest themselves only in a homozygous state. Analysis (see Analysis) of this kind of phenomena is carried out during medical genetic consultations; In livestock farming, the method of analyzing sires by offspring is used. See also Mendel's laws, Epistasis (see Epistasis). Lit. at Art. Genetics (see Genetics) (see Gene).? Yu. S. Demin.
Complete information about the concept of recessivity
According to the generally accepted definition, recessiveness (from the Latin recessus - retreat, removal), one of the forms of phenotypic manifestation of genes. When crossing individuals that differ in a certain characteristic, G. Mendel discovered that in the first generation hybrids one of the parental characteristics disappears (recessive), and the other appears (dominant) (see Mendelism, Mendel's laws). The dominant (see House) form (allele) of the gene (A) manifests its effect in homo- and heterozygous states (AA, Aa), while the recessive allele (a) can manifest itself only in the absence of the dominant (a) (see Heterozygosity ( see Heterozygosity), Homozygosity (see Homozygosity)). Thus, a recessive allele is a suppressed member of an allelic pair of genes. Dominance (see Dominance) (see House) or R. allele is revealed only through the interaction of a specific pair of allelic genes. This can be observed by analyzing a gene that occurs in several conditions (the so-called multiple allele series). A rabbit, for example, has a series of 4 genes that determine the color of the coat (C - solid color, or agouti; cch - chinchilla; ch - Himalayan color; c - albino). If a rabbit has the genotype Ccch, then in this combination cch is a recessive allele, and in combinations cchch and cchc it dominates, causing the color of the chinchilla. The nature of the manifestation of a recessive trait can change under the influence of external conditions. Thus, Drosophila has a recessive mutation - “rudimentary wings”, which in a homozygote at an optimal temperature (25? C) leads to a sharp decrease in the size of the wings. When the temperature rises to 30? C, the size of the wings increases and can reach the norm, i.e., manifest itself as a dominant trait. The recessive effect of a gene may be due to a slowdown or change in the course of any biochemical function. A significant part of congenital metabolic disorders in humans is inherited in a recessive manner, i.e., the clinical picture of the disease is observed only in homozygotes. In heterozygotes, the disease does not manifest itself due to the functioning of the normal (dominant) allele (see "Molecular (see Mol) diseases", Hereditary diseases (see Hereditary diseases)). Most recessive lethal mutations are associated with disruption of vital biochemical processes, which leads to the death of individuals homozygous for this gene. Therefore, in the practice of animal husbandry and crop production, it is important to identify individuals who are carriers of recessive lethal and semi-lethal mutations, so as not to involve harmful genes in the selection process. The effect (see Effect) of inbreeding depression during inbreeding (see Inbreeding (see Inbreeding)) is associated with the transition of harmful recessive genes into a homozygous state and the manifestation of their action. At the same time, in breeding practice, recessive mutations often serve as valuable starting material. Thus, their use in mink breeding made it possible to obtain animals with skins of platinum, sapphire and other colors, which are often valued more than dark brown wild-type minks. When carrying out genetic analysis, a hybrid is crossed with a parental form that is homozygous for recessive alleles. This way it is possible to determine hetero- or homozygosity for the analyzed gene pairs. Recessive mutations play an important role in the evolutionary process. The Soviet geneticist S.S. Chetverikov showed (1926) that natural populations contain a huge number of diverse recessive mutations in the heterozygous state. Wed. Dominance (see Dominance) (see House), Codominance (see Codominance). ? Lit.: Lobashev M. E., Genetics (see Genetics) (see Gene), 2nd ed., L., 1967; McKusick V., Genetics (see Genetics) (see Gene) of man, trans. from English, M., 1967. ? M. M. Aslanyan.
Each organism is characterized by a certain set of chromosomes, which is called a karyotype. The human karyotype consists of 46 chromosomes - 22 pairs of autosomes and two sex chromosomes. In women, these are two X chromosomes (karyotype: 46, XX), and in men, one X chromosome and the other Y (karyotype: 46, XY). Each chromosome contains genes responsible for heredity. Karyotype research is carried out using cytogenetic and molecular cytogenetic methods.
Karyotyping is a cytogenetic method that allows you to identify deviations in the structure and number of chromosomes that can cause infertility, other hereditary diseases and the birth of a sick child.
In medical genetics, two main types of karyotyping are important:
studying the karyotype of patients
prenatal karyotyping - study of fetal chromosomes.
Chromosomal aberration- a mutation that changes the structure of chromosomes. With chromosomal aberrations, chromosomal rearrangements occur within:
A section of a chromosome is lost; or
A section of a chromosome is doubled (DNA duplication); or
A section of a chromosome is transferred from one place to another; or
Sections of different (non-homologous) chromosomes or entire chromosomes merge.
lat.Aberration - to deviate
Basics of genetics
The central concept of genetics is the “gene”. This is an elementary unit of heredity, characterized by a number of characteristics. At its level, a gene is an intracellular molecular structure. In terms of chemical composition, these are nucleic acids, in which the main role is played by nitrogen and phosphorus. Genes are located, as a rule, in the nuclei of cells. They are present in every cell, and therefore their total number in large organisms can reach many billions. According to their role in the body, genes represent a kind of “brain center” of cells.
Genetics studies two fundamental properties of living systems: heredity and variability, that is, the ability of living organisms to transmit their characteristics and properties from generation to generation, as well as to acquire new qualities. Heredity will create a continuous continuity of characteristics, properties and developmental features over a number of generations. Variation provides material for natural selection, creating both new variants of characteristics and countless combinations of pre-existing and new characteristics of living organisms.
The traits and properties of an organism that are inherited are fixed in the genes, sections of the DNA molecule (or chromosome), which determine the possibility of developing one elementary trait or the synthesis of one protein molecule. The totality of all the characteristics of an organism is called a phenotype. The set of all genes of one organism is called a genotype. The phenotype is the result of the interaction between the genotype and the environment. These discoveries, terms and their definitions are associated with the name of one of the founders of genetics, V. Johansen.
Genetics was based on the patterns of heredity discovered by the Czech scientist Gregor Mendel during a series of experiments on crossing different varieties of peas. The crossing of two organisms is called hybridization, the offspring from the crossing of two individuals with different heredity is called a hybrid, and an individual is a hybrid. During these studies, Mendel discovered quantitative patterns of inheritance of traits. Mendel's merit in the field of genetics lies, first of all, in a clear presentation and description of the laws of genetics, which were called Mendel's laws in honor of their discoverer.
When crossing two organisms belonging to different pure lines, the entire first generation of hybrids (F1) will be uniform and will carry the trait of one of the parents. This is Mendel's first law. The manifestation of a trait depends on which gene is dominant and which is recessive. It is also important to note that a mutation can occur in different parts of the same gene. This results in a series of multiple alleles. Alleles - These are different states of the same gene. In this case, several variants of one trait arise (for example, in the Drosophila fly, a series of alleles for the eye color gene are known: red, coral, cherry, apricot, up to white).
Second Law Mendel states that when two descendants of the first generation are crossed with each other, two heterozygous individuals (Aa) are observed in the second generation in a certain numerical ratio: for phenogyne 3:1, but for genotype 1:2:1 (AA+2Aa+aa).
When crossing two homozygous individuals that differ from each other in two or more pairs of alternative traits, the genes and their corresponding traits are inherited independently of each other and are combined in all possible combinations. This is Mendel's third law, which appears when the genes under study are located on different chromosomes.
An important step in the development of genetics was the creation of the chromosomal theory of heredity associated with the name of T. Morgan. He revealed patterns of inheritance of traits whose genes are located on the same chromosome. Their inheritance goes together. This is called genetic linkage (Morgan's law). This discovery was due to the fact that Mendel's third law did not apply in all cases. Morgan logically concluded that any organism has many characteristics, but the number of chromosomes is small. Therefore, there must be many genes on each chromosome. He discovered the pattern of inheritance of such genes.
Genetics also explained the origin of sex differences. So, in humans, out of 23 pairs of chromosomes, 22 pairs are the same in male and female organisms, and one pair is different. It is thanks to this pair that the two sexes differ; these chromosomes are called sex chromosomes. The sex chromosomes in women are the same, they are called X chromosomes. In addition to the X chromosome, men also have a Y chromosome. If an egg is fertilized by a sperm carrying an X chromosome, a female organism develops, but if a sperm containing a Y chromosome penetrates the egg, a male organism develops. In birds, the opposite is true - males have two X chromosomes, and females have an X and a Y chromosome.
The next important stage in the development of genetics was discovery of the role of DNA in the transmission of hereditary information in the 30s of the XX century. The discovery of genetic patterns at the molecular level began, and a new discipline was born - molecular genetics. In the course of research, it was found that the main function of genes is to encode protein synthesis. For these studies in 1952, J. Beadle, E. Taytum and J. Lederberg were awarded the Nobel Prize.
Then the fine structure of genes was established (1950, S. Benzer), the molecular mechanism of the functioning of the genetic code, the language in which genetic information is written was understood (nitrogen bases: adenine (A), thymine (T), cytosine (C), guanine (D), a five-atomic sugar and a phosphoric acid residue. In this case, adenine always combines with thymine of another DNA strand, and guanine with cytosine). The mechanism of DNA replication (transfer of hereditary information) was deciphered. It is known that the sequence of bases in one strand exactly determines the sequence of bases in another (the principle of complementarity). During reproduction, the two strands of the old DNA molecule separate, and each becomes a template for the reproduction of new DNA strands. Each of the two daughter molecules necessarily includes one old polynucleotide chain and one new one. The duplication of DNA molecules occurs with amazing precision - the new molecule is absolutely identical to the old one. This has a deep meaning, because a violation of the DNA structure, leading to a distortion of the genetic code, would make it impossible to preserve and transmit genetic information that ensures the development of the body’s inherent characteristics. The trigger for replication is the presence of a special enzyme - DNA polymerase.
Variability is the ability of living organisms to acquire new characteristics and properties. Variability is the basis for natural selection and evolution of organisms. There are hereditary (genotypic) and non-hereditary (modification) variability.
The limits of modification variability are called reaction norms; they are determined by the genotype. This variability depends on the specific environmental conditions in which the individual organism is located and makes it possible to adapt to these conditions (within the normal reaction limits). Such changes are not inherited.
The discovery of the ability of genes to undergo restructuring and change is the largest discovery of modern genetics. This ability for hereditary variability was given to genetics the name mutation (from the Latin mutatio - change). It occurs due to changes in the structure of a gene or chromosomes and serves as the only source of genetic diversity within a species. Mutations are caused by all sorts of physical (cosmic rays, radioactivity, etc.) and chemical (various toxic compounds) causes - mutagens. Thanks to the constant mutation process, various gene variants arise, constituting a reserve of hereditary variability. Most mutations are recessive in nature and do not appear in heterozygotes. This is very important for the existence of the species. After all, mutations turn out to be, as a rule, harmful, since they disrupt the finely balanced system of biochemical transformations. Holders of harmful dominant mutations, which immediately manifest themselves in both homo- and heterozygous organisms, often turn out to be non-viable and die at the earliest stages of life.
But when environmental conditions change, in a new environment, some previously harmful recessive mutations that make up the reserve of hereditary variability may turn out to be useful, and carriers of such mutations receive an advantage in the process of natural selection.
Variation can be caused not only by mutations, but also by combinations of individual genes and chromosomes, for example, during sexual reproduction - genetic recombination. Recombination can also occur due to the inclusion of new genetic elements introduced from outside into the cell genome - migrating genetic elements. Recently, it has been found that even their very introduction into a cell gives a powerful impetus to multiple mutations.
One of the most dangerous types of mutagens are viruses (from the Latin virus - poison). Viruses are the smallest living creatures. They do not have a cellular structure and are not capable of synthesizing protein themselves, so they obtain the substances necessary for life by penetrating a living cell and using foreign organic substances and energy. Viruses cause many diseases in humans.
Although mutations are the main suppliers of evolutionary material, they are random changes that obey probabilistic, or statistical, laws. Therefore, they cannot serve as a determining factor in the evolutionary process. True, some scientists consider the mutation process as such a factor, forgetting that in this case it is necessary to recognize the initial usefulness and suitability of absolutely all random changes that arise, which contradicts observations in nature and experiments in selection. In reality, besides selection - natural or artificial, there is no other means of regulating hereditary variability. Only random changes that prove beneficial under certain environmental conditions are selected in nature or artificially by man for further evolution.
Based on these studies, the theory of neutral mutations was created (M. Kimura, T. Ota, 1970 - 1980s). According to this theory, changes in the functions of the protein synthesizing apparatus are the result of random mutations that are neutral in their evolutionary consequences. Their true role is to provoke genetic drift, which has been well known since the 1940s - the phenomenon of changes in the frequency of genes in populations under the influence of completely random factors. On this basis, the neutralist concept of non-Darwinian evolution was proclaimed, the essence of which is that natural selection does not work at the molecular genetic level. This means that variability at this level is not a factor in evolution. And, although these ideas are not generally accepted among biologists today, it is obvious that the direct arena of action of natural selection is the phenotype, that is, a living organism, the ontogenetic level of organization of the living.
Non-Mendelian genetics
The genius of Mendel's laws lies in their simplicity. The rigorous and elegant model built on these laws has served geneticists as a point of reference for many years. However, in the course of further research, it turned out that only relatively few genetically controlled Traits obey Mendel’s laws. It turned out that in humans, the majority of both normal and pathological characteristics are determined by other genetic mechanisms, which began to be designated by the term “non-Mendelian genetics.” There are many such mechanisms, but in this chapter we will consider only a few of them, referring to relevant examples, namely: chromosomal aberrations (Down syndrome); sex-linked inheritance (color blindness); imprinting (Prader-Willi, Engelman syndromes); emergence of new mutations (development of cancer); expansion (insertion) of repeating nucleotide sequences (Duchenne muscular dystrophy); inheritance of quantitative traits (complex behavioral characteristics).
DNA as the basis of heredity
For psychogenetics, the main object of study of which is the nature of individual differences, familiarity with the structure and mechanisms of functioning of DNA is important for understanding how genes influence human behavior. Genes do not code behavior itself. They determine the amino acid sequences in proteins that direct and create the basis for the cell's chemical processes. Between the gene and behavior lie numerous biochemical events, the discovery and understanding of which is a most interesting problem being solved by various sciences. The variability of a gene, the fact that it exists in multiple forms (alleles), creates the basis for the formation of individual differences - somatic, physiological, psychological. It is in this sense that they say that DNA is the material basis of heredity: genetic variability creates, in the context of environmental variability, phenotypic variability. Nucleic acids
Nucleic acids are non-periodic polymers. There are two types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA is contained mainly in the chromosomes of the cell nucleus; RNA is found in both the nucleus and the cytoplasm.
In all living organisms (with the exception of some viruses), hereditary information is transmitted from generation to generation using DNA molecules. Each cell of the human body contains about a meter of DNA. Typically, DNA consists of two complementary strands that form a right-handed double helix. Recall that each chain is a linear polynucleotide consisting of four nitrogenous bases: adenine (A), guanine (G), thymine (7) and cytosine. When forming a DNA double helix, A of one strand always pairs with 7" of the other, and G with C. These bases are called complementary. The principle of selectivity of this bond is extremely simple and is determined by the principle of the presence of free space. The fact is that the DNA spiral ladder is clamped with two sides into the “railing” that limits it, consisting of sugar (deoxyribose) and phosphate groups. Pairs A-- T and G-- C fit into the “interrail” space flawlessly, but any other pairs simply cannot fit in - they do not fit Thus, in terms of their geometric dimensions, adenine and guanine (12 angstroms in length*) are much larger than thymine and cytosine, the length of each of which is 8 angstroms. The distance between the “railings” is the same everywhere and is equal to 20 angstroms. So pairs A-- T and G--C are not random: their structure is determined both by size (one base should be small and the other large) and by the chemical structure of the nitrogenous bases.Obviously, the two DNA strands are complementary to each other.
The two strands of DNA are connected to each other by hydrogen bonds that link pairs of nucleotides. A pairs with G through a double hydrogen bond, and G pairs with C through a triple hydrogen bond. Hydrogen bonds are relatively weak; under the influence of certain chemical agents they are easily both destroyed and restored. The American geneticist R. Lewontin, describing the nature of the bonds in the DNA molecule, proposed a successful image of a zipper that can be opened and closed many times without any damage to the molecule itself. Features of the macromolecular structure of DNA were discovered by American scientists D. Watson and F. Crick in 1953. According to the three-dimensional model of the DNA structure they developed, the pitch of the DNA helix is approximately 34 angstroms, and each turn contains 10 nucleotides located at a distance of 18 angstroms from each other friend.
DNA has the property of covariant reduplication, i.e. its molecules are capable of copying themselves while preserving the changes that occur in them. This duplication occurs through processes called mitosis and meiosis (see Chapter I). During the process of DNA doubling (replication), which is carried out with the participation of enzymes, the DNA double helix temporarily unwinds, and a new DNA strand (complementary to the old one) is built.
The structure of DNA is dynamic: the double helix is in constant motion. The fastest processes known to us that unfold in DNA are associated with the deformation of bonds in each of its chains; these processes take picoseconds (10-12 s). The destruction and creation of bonds between complementary bases are slower processes; they take from a thousandth of a second to an hour.
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Topic 1. The subject of psychogenetics, its changes in the process of development. The place of psychogenetics in the system of psychological knowledge. (2 hours)
Basic concepts: psychogenetics, subject of psychogenetics, behavior, tasks of psychogenetics, genetic and environmental factors, eugenics, positive and negative eugenics, gene, mutation, genotype, phenotype, individual differences, heredity, differential psychology, variability, intelligence, talent, racial differences, sexual differences.
Plan:
Psychogenetics (genetics of human behavior) as a scientific discipline. Problems of psychogenetics. Subject of study
History of psychogenetics. Main periods of development of behavioral genetics
The origins of the genetics of human behavior (F. Galton, V.M. Florinsky, G. Mendel)
The formation of psychogenetics as an independent scientific discipline
Stages of accumulation of empirical material
The current stage of development of psychogenetics
History of the development of psychogenetics in Russia
Egorova, M.S. Genetics of behavior: psychological aspect. M., 1995.
Malykh S.B., Egorova M.S., Meshkova T.A. Fundamentals of psychogenetics. M., 1998.
Ravich-Scherbo I.V., Maryutina T.M., Grigorenko E.L. Psychogenetics. M., 1999.
Problems of psychogenetics. Subject of study.
Psychogenetics is a field of science that arose at the intersection of psychology and genetics. As a part of psychology, psychogenetics belongs to a broader field - the psychology of individual differences (differential psychology), which, in turn, is part of general psychology. Differential psychology is the study of individual differences between people or groups of people. One of the tasks of differential psychology is to study the origin of individual differences, namely the role of biological and social causes of their occurrence. One of the areas of research in this area is the study of the role of hereditary and environmental factors in the formation of interindividual variability in various psychological and psychophysiological characteristics of a person. This is the main subject of psychogenetics. Also, psychogenetics can be classified as a discipline that makes up the natural scientific foundations of psychology.
Psychogenetics (behavioral genetics) is an interdisciplinary field of knowledge, borderline "between psychology (more precisely, differential psychology) and genetics; the subject of its research is the relative role and effect of hereditary and environmental factors in the formation of differences in psychological and psychophysiological characteristics. In recent years, the field of psychogenetics Research also includes individual development: mechanisms of transition from stage to stage, and individual development trajectories.
In Western literature, the term “behavioral genetics” is usually used to refer to this scientific discipline. However, the essence does not change much from this - the purpose of the study, in any case, is to try to find out how genetic and environmental factors are involved in the formation of the phenotype. Differences may be due to which phenotypic traits are included in the analysis. It is important to keep in mind that the characteristics of a person’s behavior or the properties of his psyche represent special signs of the phenotype. The psychogenetic analysis of human behavior is also extremely complex because for a person, the participation of the environment in the formation of the phenotype is not simply a matter of influence “here and now.” The environment is not only the physical environment, but is manifested mainly in complex and multiple cultural and social influences that have their own history.
At the present stage of development, the goal of most psychogenetic research is to determine the relative contribution of genetic and environmental factors to the formation of individual psychological differences, as well as to study possible mechanisms that mediate genetic and environmental influences on the formation of multi-level mental properties.
Thus, the task of psychogenetics is to clarify not only hereditary, but also environmental reasons for the formation of differences between people according to psychological characteristics. The results of modern psychogenetic research provide information about the mechanisms of action of the environment to the same, if not greater, extent as about the mechanisms of action of the genotype. In general terms, it can be argued that the main role in the formation of interindividual variability in psychological characteristics belongs to the individual (unique) environment. Its role is especially high for personality and psychopathological traits. Increasing emphasis in psychogenetic research is being placed on the relationship between family socioeconomic level or length of schooling with the results of children's intelligence tests. Even such formal characteristics as the parameters of the family configuration (number of children, birth order, interval between births) turn out to be important for the individualization of the child - both in the cognitive and personal spheres.
Thus, we can define the range of problems of psychogenetics:
The role of heredity and environment in the formation of human diversity (behavioral, psychological) is normal
Hereditary and environmental causes of deviant behavior and mental illness
The role of heredity and environment in development
The study of environmental factors in the formation of human behavior (a new term has appeared - from the English environment - environment)
Search for specific genes and their localization on chromosomes
Animal modeling, etc.
^ 2. History of psychogenetics. The main periods of development of behavioral genetics.
Most trends in science arise in connection with the demand of society or are born as a result of human practical activity. If we talk about genetics in general, it is quite obvious that practical genetics has its roots in ancient times. Written evidence has been preserved that in ancient civilizations work was carried out on the selection of plants and animals. Ancient natural philosophers and doctors tried to penetrate the secrets of human heredity.
The basis for their conclusions were everyday observations: the similarity of parents and descendants (not only in appearance, but also in character, gait, abilities), the participation of male seed in conception, and the inheritance of certain diseases and deformities.
The ancients were spontaneous geneticists, rather breeders, since people began breeding farm animals and plants from time immemorial. Of course, not only the productive qualities of animals, but also their behavior attracted attention, because the disposition of an animal plays an important role in human communication with it.
However, one of the sources of psychogenetics, as well as genetics, is the theory of evolution developed by Charles Darwin in the 19th century. The essence of Darwin's theory is as follows. First, individuals within each species exhibit variability in morphological and physiological characters, and this variability occurs randomly. Secondly, this variability is inherited. Thirdly, due to the limited necessary resources, individuals of a given population struggle to survive. The fittest survive and leave offspring with the same characteristics. As a result of this natural selection of the most adapted individuals, representatives of a given species become increasingly better adapted to environmental conditions. Thus, the mechanism of evolution is based on three fundamental factors - variability, heredity and natural selection.
The emergence of evolutionary theory gave impetus to research into the phenomenon of heredity.
The history of the development of genetics of human behavior can be divided into four main periods:
1865-1900 - the birth of the genetics of human behavior;
1900-1924 - formation of behavioral genetics as an independent scientific discipline;
1924-1960 - accumulation of empirical material;
Let us briefly describe each of these stages and dwell in a little more detail on the history of the development of the genetics of human behavior in Russia.
^ 2.1 The emergence of behavioral genetics (1865-1900)
F. Galton in 1865 substantiated the idea of heredity and the possibility of improving human nature through the reproduction of gifted people (these ideas were the basis of eugenics). He conducted empirical studies of the heritability of human behavior and showed:
A) the likelihood of talent manifesting itself in the families of outstanding people is much higher than in society as a whole.
B) the likelihood that a relative of an outstanding person will be talented increases as the degree of relationship increases.
This allowed Galton to formulate the law of ancestral inheritance.
Galton's merits:
Creation of a methodological arsenal of psychogenetics
Development of basic variation statistics.
The use of twins to identify the type of heredity
He developed methods for measuring human psychological functions that serve to assess individual differences between people.
Thus, Galton defined the basic approaches and concepts of behavior genetics.
^ 2.2 The formation of behavioral genetics as an independent scientific discipline (1900 – 1924).
In 1900 the secondary discovery of Mendel's law, the mathematical apparatus of genetics is developing, there is an arrangement between representatives of the biometric scale (studies quantitative characteristics of continuous changing characteristics), they denied the discreteness of heredity and from their point of view, the laws of G. Mendel are not applicable to complex characteristics (higher organisms) and genetics talked about the discrete nature of heredity, therefore, from their point of view, evolution is based on abrupt hereditary changes - mutations.
Within the framework of the concept, many factors occurred thanks to genetics and biometrics.
The concept was based on the fact that Mendeenile's mechanism of discrete inheritance was applied to continuously complex traits.
Thus, the main point of the concept is that polygenic differences between individuals can lead to phenotypic ones.
^ 2.3. Stages of accumulation of empirical material
In the 20s G. Siemens a relatively reliable method for identifying MZ and DZ twins was developed - polysymptomatic similarity diagnosis(Siemens H., 1924). It has been shown that reliable identification of zygosity of twins is possible only on the basis of comparison of a large number of physical characteristics (eye color, hair color, shape of the nose, lips, ears, blood type, etc.). At the same time, G. Siemens proposed using not only MZ, but also DZ twins for research. With this publication, G. Siemens laid the foundations for the scientific application of the twin method in human genetics.
The emergence of the polysymptom similarity method and the development of measurement methods in experimental psychology stimulated twin studies in behavioral genetics. Until this point, in studies of the hereditary determination of psychological characteristics, the family method was most often used. So, for example, also in 1904 Karl Pearson conducted research on the similarity of mental development among siblings. It turned out that the correlation coefficient for the level of mental development, which was assessed based on teacher ratings, was 0.52 for the brothers. This level of similarity corresponded to the level of similarity in physical characteristics, on the basis of which K. Pearson concluded about the influence of heredity on this characteristic (Pearson C., 1904). The development of psychodiagnostic methods has made it possible to use standardized tests. In one of the first works using Binet-Simon test Quite high correlations (0.61) were found between siblings (Gordon K., 1919).
In the first twin studies, as a rule, comparisons of same-sex and opposite-sex twins were used (Fuller J., Thomson W., 1978). In the 20-30s, after the advent of fairly reliable methods for diagnosing zygosity, the number of twin studies increased significantly. The hereditary dependence of human morphological characteristics was studied (Dahlberg, 1926, Bunak V.V., 1926, Verschuer O., 1927, etc.), dermatoglyphics (Newman H., 1930; Vershuer O., 1933; Volotskoy M.V., 1936 etc.), cardiovascular system (Kabakov I.B., Ryvkin I.A., 1924, Vershuer, 1931/32; Malkova N.N., 1934, etc.), motor skills (Frischeisen-Kohler I. 1930; Lehtovaara, 1938; Mirenova A.N. et al.), intelligence (Tallman G., 1928; Holzinger K., 1929, etc.) and personal characteristics (Carter H., 1933; Newman H., Freeman F., Holzinger J., 1937, etc.). We will not dwell on these works in detail, since some of them have only historical significance, while others are analyzed in subsequent chapters of the book. Let us dwell only on those works that were of fundamental importance for the development of human genetics.
Such works primarily include the first studies of adopted children. The essence of the method is to compare children separated at birth from their biological relatives and raised in families of adoptive parents with children raised by biological parents. Research on adopted children began with the publication in 1919 the work of K. Gordon, which showed that the similarity of intelligence scores (r = 0.53) of siblings raised in orphanages is practically no different from the similarity of siblings living at home. In 1928, work was published using the classic version of the “adopted children” method. The author of this work, B.Barks, showed that the correlation coefficients of intelligence indicators of adopted children and their adoptive parents are significantly lower (r = 0.07 for father and r = 0.19 for mother) than the corresponding correlations with biological parents (0.45 and 0.46 for father and mother, respectively). These days, the stepchild method is widely used in behavioral genetics.
A private version of the adopted children method can be considered separated twins method. The first work to use this method was a study H. Newman, F. Freeman and K. Holzinger performed in 1937 (Newman H. et al., 1937). In this, which has become a classic, work, for the first time, along with a sample of MZ and DZ twins raised together, 19 pairs of MZ twins raised separately were studied. The twins completed a series of standardized intelligence and personality tests: the Stanford-Binet test, the Stanford Achievement Test, the Woodworth-Matthews Personality Inventory, the Temperament Inventory, and a number of other tests. Despite the fact that the correlation coefficients of separated MZ twins were slightly lower than the same coefficients of MZ twins raised together, they were still significantly higher than those of DZ. The method of separated twins allows for an almost perfect separation of genetic and environmental sources of variation in experiments and is constantly used in behavioral genetics.
Thus, from the 20s to the 60s, the basic methods of behavior genetics were developed and extensive experimental material was obtained concerning a wide variety of human characteristics - from morphology to complex and complex psychological characteristics.
^ 2.4. The current stage of development of psychogenetics
In the second half of the twentieth century, the number of researchers studying the problems of inheritance of psychological characteristics increased significantly. In 1960, the scientific society “Behavior Genetics Association” was created with its own journal “Behavior Genetics”. It was 1960 that can be considered the official date of recognition of behavioral genetics as an independent field of science.
Most of the efforts in behavioral genetics in the 60-70s were aimed at studying the role of genotype and environment in the formation of individual differences in cognitive and personality spheres. In the early 80s, the interest of researchers was attracted by the possibilities of behavioral genetics methods for studying the environment. As is known, family resemblance is due to both genetic and environmental factors. Quantitative genetics methods make it possible to separate the influence of these factors. For example, comparing the similarities between adoptive parents and children makes it possible to assess the role of the family environment. Similar studies have shown the important role of environmental influences in the formation of individual differences. It was the genetics of behavior that played a major role in establishing the fact that the effect of environmental factors on mental development is not the same for members of the same family. It turned out that the variability of psychological characteristics is largely due to living conditions (different friends, hobbies, individual life experiences) that differ among children of the same family. Different experiences lead to differences in behavior.
During these same years, the problem of development attracted much attention from researchers in behavioral genetics. Works devoted to the study of the influence of genetic and environmental factors on the formation of individual characteristics of psychological and psychophysiological characteristics during development still occupy a central place in the genetics of behavior.
Characterizing the current stage of development of behavioral genetics, one cannot help but touch upon the emergence of new methods of behavioral genetics, the influence of which on the development of research in this area can hardly be overestimated.
First of all - this linkage analysis method. If data on successive generations is available, the degree of linkage between pairs of loci can be determined, which makes it possible to use easily identified genes as markers of other genes that determine certain human characteristics (Ott J., 1985). The linkage analysis method allows you to localize genes associated with a hereditary disease or some other clearly expressed trait.
The development of computer technology has stimulated the use of behavior genetics methods of multivariate genetic analysis. When genetically analyzing psychological and psychophysiological characteristics, the analysis of integral characteristics is especially interesting, since in psychology many psychological phenomena are identified based on the analysis of relationships between various variables, such as the “g” factor. The use of multivariate genetic analysis makes it possible to assess the nature of the relationships between various characteristics, including those related to different levels of phenotype manifestation (from biochemical to psychological).
The development of multivariate genetic analysis was greatly influenced by latent variable theory. Latent variable models are understood as a set of statistical models that describe and explain observed data by their dependence on unobservable (latent) factors that can be reconstructed using certain mathematical methods. An example of a latent variable model is factor analysis. In 1969, K. Jöreskog proposed a new method for testing hypotheses about data structure. This method of “groping for hypotheses” is called confirmatory factor analysis. In contrast to the traditional exploratory version of factor analysis, the main principle of confirmatory factor analysis is that the researcher, as a hypothesis (a priori), forms the structure of the expected matrix of factor loadings (structural hypothesis), which is then subjected to statistical testing. This feature of confirmatory factor analysis, as well as the possibility of comparing the factor structures of several groups of observations, was of great importance for genetic analysis. In 1977 Nicholas Martin and Lyndon Eaves(Martin N., Eaves L., 1977) successfully used K. Jöreskog’s approach for genetic analysis of covariance structures.
Model of linear structural relationships by K. Jöreskog and the corresponding computer program ^ LISREL (LInear Structural RELation), introduced in 1973 , have given behavioral genetics researchers a powerful tool for genetic analysis of covariance structures. Since the 1980s, LISREL has been one of the most popular computer programs that makes it possible to test the most complex hypotheses.
^ 3. History of the development of psychogenetics in Russia
Eugenics movement
On November 19, 1921, the first meeting of the Russian scientific eugenics society was held at the Institute of Experimental Biology. At this meeting, an outstanding biologist was elected chairman of the society N.K.Koltsov. Subsequently, not only biologists and doctors, but also representatives of other sciences, including psychologists, took part in the work of the society. For example, in 1922 G.I. Chelpanov, founder of the first Russian Institute of Psychology, twice made presentations at a meeting of the Russian Eugenics Society. At the 20th meeting of the society in February 1922, he delivered a report on “The Significance of Galton for Modern Scientific Psychology,” and in March he gave a report on “The Problem of the Culture of Talents (the Role of Heredity and Upbringing).” G.I. Chelpanov was far from the only psychologist who took part in the work of the Russian Eugenics Society. So, in 1923, at a meeting of the society, he gave a report “On the issue of experimental psychological research of persons especially gifted intellectually” A.P.Nechaev, a little later - G.I.Rossolimo with the report “A look at the current state of the question of the study of intellectual abilities.”
The Russian Eugenics Society considered its main tasks to be:
1) study of the laws of hereditary transmission of various properties, both normal and pathological;
2) establishment of hereditary differences in normal and pathological properties of different professional and social types;
3) study of exogenous and endogenous influences that determine the development of the trait;
4) study of the fertility of certain types.
To solve these problems, the Russian Eugenics Society intended to organize the collection of mass statistical data according to strictly methodologically justified and uniform schemes. The family eugenic survey plan included a family sheet for individual characteristics, a family sheet for several characteristics, a typological sheet for the study of homogeneous typical groups, a generic biographical sheet, a demographic family sheet and a family pedigree table.
In 1922, in Moscow, N.K. Koltsov founded "Russian Eugenics Journal", which consolidated a fairly diverse eugenics movement. In total, 7 volumes (1922 - 1930) of the magazine were published. To organize eugenic research, a special department was created at the Institute of Experimental Biology. N.K. Koltsov understood the tasks of eugenics quite broadly and included in it not only the compilation of genealogies, but also the geography of diseases, vital statistics, social hygiene, genetics of human mental characteristics, types of inheritance of eye color, hair, etc.
During these same years ^ Yu.A. Filipchenko in Leningrad, he organized the Bureau of Eugenics under the Commission for the Study of the Natural Productive Forces of Russia at the Russian Academy of Sciences and began publishing “Izvestia of the Bureau of Eugenics.”
The eugenics movement in the USSR did not last long, since the goals of the movement diverged from the official ideology. By 1930, eugenics ceased to exist in the USSR.
^ History of twin studies
The first publications of twin studies in Russia date back to the early 1900s. These are the works of S.A. Sukhanov, T.I. Yudin, V.V. Bunak, G.V. Soboleva. In 1900 S.A. Sukhanov published a work “On psychosis in twins,” in which he analyzed 30 cases of similar psychosis in twins. This work was subsequently continued T.I. Yudin, who has already described 107 cases of psychosis in twins. Of these 107 cases, in 82 cases both twins were affected, and in 25 cases only one of the pair was affected.
However, systematic studies of twins began only in 1929 at the Medical-Biological Institute(in 1935 it was renamed the Medical Genetics Institute).
The main task of the institute, according to its director, is S.G. Levita, consisted “of developing from the point of view of genetics and related sciences (biometrics, cytology, developmental biology, evolutionary theory) the problems of medicine, anthropology and psychology, as well as the development of problems of theoretical anthropogenetics” (Levit S.G., 1936, p. 5). The Institute adhered to an integrated approach to solving the assigned problems, for which the following departments were opened: genetics, cytology, developmental mechanics and immunobiology, internal diseases, psychology. However, the main focus of the Institute's research was the investigation of the role of genetic and environmental influences in the etiology of diseases. The Institute studied the hereditary cause of a number of diseases, such as Graves' disease (S.G. Levit, I.A. Ryvkin), bronchial asthma (N.N. Malkova), eunuchoidism (I.B. Likhtsier), stomach ulcer and duodenum (A.E. Levin), diabetes (S.G. Levit, L.N. Pesikova) and others. The institute's workers obtained interesting data on the role of heredity in the formation of physiological characteristics of childhood (L.Ya. Bosik), the structure of some parts of the skeletal system (I.B. Gurevich), features of the electrocardiogram (I.A. Ryvkin., I.B. Kabakov). The Institute also paid great attention to the development of mathematical methods for analyzing twin studies (M. V. Ignatiev).
A psychological direction of work was proposed A.R. Luria, who headed the psychological department of the institute (S.G. Levit, 1934).
The institute conducted research into the hereditary conditioning of motor functions, various forms of memory, the level of mental development, attention, and characteristics of intelligence. Particularly interesting are the studies on active effects on humans conducted by the institute’s staff. It's about testing nutrition, treatment and education methods. For this kind of research, we used the “control” twin method, with the help of which the effectiveness of various methods of teaching literacy (A.N. Mirenova, Govyadinova), the development of constructive activity of a preschooler (V.N. Kolbanovsky; A.R. Luria., A.N.) was tested. .Mirenova). Let's take a closer look at the latest work.
As S.G. Levit and A.R. Luria write in the article “Genetics and Teachers” (magazine “For Communist Education” dated December 2, 1934), many preschool teachers have high hopes for the use of technical design in kindergarten. However, they have questions about teaching methods - which of them is most effective for the development of a child’s constructive activity (copying lined up figures, building using contour models, free design, etc.). To answer this question, a special study of five pairs of MZ twins was conducted. The twins were divided into two groups, with the partners of each pair in different groups. These groups were trained using different methods. Children from the first group were asked to simply copy figures built from cubes for two and a half months. Another group of twins were taught constructive activities using a different method. They were asked to build similar figures, but the difference was that the models they had to build on were covered with paper, and the child had to mentally disassemble them into their component elements and, after such an analysis, find the necessary cubes. At the end of the training, it turned out that the members of the pair trained using the second method were much ahead of their partners, whereas before the training both members of the pair showed the same results. This study showed that training consisting of repeated repetition of simple visual operations did not significantly develop the child's constructive activity. Training, based on complex visual analysis, not yet developed in the child, led to a significant development of constructive operations (Luria A.R., Mirenova A.N., 1936).
A number of specific studies conducted by employees of the Medical Biological Institute are also discussed in the relevant sections of this book.
In general, it should be said that the Medical-Biological, and subsequently the Medical-Genetic Institute was unique for its time both in terms of its goals and the results of the work carried out by its employees. More than 700 pairs of twins were comprehensively studied by doctors and psychologists at the Institute. The system that existed at the institute for providing all types of outpatient and inpatient medical care for twins ensured constant monitoring of each examined pair. A special kindergarten for twins was also created at the Institute, where they were under the constant supervision of doctors and psychologists (Levit S.G., 1936).
Unfortunately, the events that unfolded around genetics (during the period of dominance in biological science by T.D. Lysenko) in the 30s did not bypass the Medical Genetics Institute. In 1936, open persecution of S.G. Levit and the institute as a whole began, which led to its closure in the summer of 1937. In 1938, S.G. Levit was arrested and subsequently executed. After this, research on the genetics of behavior in the USSR ceased. And only after the weakening of T.D. Lysenko’s position in the 60s, scientific work in this direction became possible again.
The resumption of domestic psychogenetic research is associated with the study of the nature of interindividual differences in the properties of the nervous system. These studies were started by employees of the Research Institute of General and Educational Psychology in the laboratory of B.M. Teplov - V.D. Nebylitsyn, and since 1972 they continued (under the leadership of I.V. Ravich-Shcherbo) in a special laboratory, the main task of which was to conduct psychogenetic research. The theoretical basis for the research that began was the concept of the properties of the nervous system (SNS), developed by B.M. Teplov and his student V.D. Nebylitsyn. Ideas about the basic, innate nature of the nervous system served as an incentive to study the role of hereditary factors in the formation of individual characteristics of the nervous system.
The stages of the path traversed by the laboratory in the 70-80s represent a consistent transition from the study of the nature of the SNS as the physiological basis of individuality to the analysis of the relationship between the properties of the nervous system and psychological characteristics and to the study of the role of hereditary and environmental factors in the formation of individual diversity of all kinds of psychological and psychophysiological characteristics of a person.
Almost all studies conducted in the laboratory in the 70s were aimed at testing the mentioned assumption about the innate, hereditarily determined nature of the individual characteristics of the functioning of the central nervous system that underlie the SNS (Shlyakhta N.F., 1978; Shibarovskaya G.A. , 1978; Vasilets T.A., 1978, etc.). In the same years, registration of bioelectrical brain activity in twins began to be used, initially as one of the indicators of the SNS (Ravich-Shcherbo I.V. et al., 1972; Shlyakhta N.F., 1972, 1978; Shibarovskaya G.A., 1978), and then as an independent bioelectric phenomenon (Meshkova T.A., 1976; Belyaeva E.P., 1981; Gavrish N.V., 1984).
The use of the technique of isolating evoked potentials (EPs) made it possible to approach the analysis of the heritability of neurophysiological mechanisms of information processing. The first work in this direction was devoted to the analysis of visual EPs (T.M. Maryutina, 1978). Subsequently, the list of studied neurophysiological indicators was expanded to include such indicators as auditory EP (Kochubey B.I., 1983), brain potentials associated with movement (Malykh S.B., 1986), conditioned negative wave (Malykh S.B. ., 1990).
Psychogenetic studies of independent psychological characteristics were initially carried out in accordance with the theoretical concepts of differential psychophysiology, which was manifested in an orientation towards dynamic rather than meaningful characteristics. At first, the list of studied characteristics was practically exhausted by the characteristics of sociability, anxiety and emotionality (Egorova M.S., Semenov V.V., 1988).
Since the beginning of the 80s, psychological issues in laboratory research have begun to change. The main subject of the study is cognitive characteristics - intelligence and cognitive abilities (see review: Egorova M.S., 1988). Since that time, experimental studies have been carried out outside the theoretical context of differential psychophysiology, while maintaining ideas about the hierarchical structure of individuality. A possible prospect is a joint psychogenetic analysis of psychological and psychophysiological characteristics, i.e. consideration of psychophysiological characteristics as a mediating link between genotype and psychological characteristics.
In the late 80s, one of the main topics of discussion in the laboratory became the question of the specifics of human psychophysiological and psychological traits included in genetic research, due to the fact that data was accumulating indicating the dependence of the mechanisms of hereditary determination of psychological and psychophysiological traits on their psychological structure .
More in 1978 by T.A. Panteleeva it was shown that genetic control of the parameters of sensorimotor activity is detected only at the level of high automation of the skill. Then in the study T.M. Maryutina It was found that the genetic control of visual EP parameters varies depending on the experimental situation in which the parameter under study is included. The study of the genetic determination of integral (systemic) psychophysiological formations, such as defensive and indicative reactions (Kochubey B.I., 1983), also confirmed the dependence of the nature of hereditary determination on the specificity of the studied link of the corresponding reaction. This dependence was most clearly revealed in the study of brain potentials associated with movement (Malykh S.B., 1986). It turned out that the genetic control of PMSD parameters for the same, according to the biomechanical scheme, movement depends on the place that this movement occupies in the psychological structure of the action. Genetic control is more pronounced when movement is only a means of execution, and not the goal of the action.
Thus, these data indicate that phenotypically the same psychophysiological trait, i.e. a trait that has the same external manifestations can differ significantly in its psychological structure and, accordingly, in the relative contribution of genotypic and environmental determinants to its variability.
Data on the age-related dynamics of genetic control of human behavior also indicate the dependence of hereditary determination on the psychological structure of the trait being studied, since the mechanisms for implementing the psychological function change in ontogenesis. Experimental studies by A.R. Luria, conducted back in the 30s, showed that at different stages of ontogenesis of the same mental function, the influence of genetic factors turns out to be different, which, in his opinion, is associated with a qualitative restructuring of the child’s mental activity.
Thus, the very logic of the scientific movement led to the organization Russia's first longitudinal study of twins, which was started in the laboratory of developmental psychogenetics of the Psychological Institute of the Russian Academy of Education in 1986.
Longitudinal tracking of the development of twins was conceived as an attempt to approach the solution of one of the main questions of developmental psychology - the question of what factors, genetic or environmental, and to what extent ensure continuity of development. Currently, the longitudinal study is ongoing, its goal is to clarify the nature of genetic control of psychological and psychophysiological traits of a person in the process of individual development.
Subject and tasks of psychogenetics. The place of psychogenetics in the study of human personality. The problem of heredity. Development of psychogenetics in world and domestic science (F. Galton, K. Stern, K. D. Ushinsky, A. F. Lazursky, N. P. Dubinin, V. P. Efronmson). Methods of psychogenetics (population, genealogical, method of adopted children, method of twins).
- concept, subject, tasks and place of PG in the system of other sciences.
- PG history:
A) GHG global and domestic.
3. Clarification of the structure of individual mental functions.
4. Identification of different types of environmental influences.
2. World psychogenetics.
Galton - test, questionnaire, survey; contributions to fingerprinting; opened an anticyclone. Two hypotheses:
All men are smarter than women (but it turned out that in some characteristics women are smarter).
Outstanding people have gifted children, i.e. pass on their abilities (but the lower classes also have their own talents).
He was the first to explore the role of heredity and environment in human intellectual characteristics.
1865 - article, book “Hereditary talent and character.” He argued that talent, human mental properties and physical characteristics are hereditary. He put forward the idea that it is possible to change the physical and spiritual appearance of a person using biological methods. The foundations of the new science of eugenics (designed to improve the quality of the population) were laid.
1876 - “Hereditary genius: a study of its laws and consequences.” He presented data on the inheritance of talent in the families of prominent people (military affairs, medicine, artists). Therefore, the likelihood of giftedness manifesting itself in the families of outstanding people is higher than in society as a whole (415 families - 1000 gifted people). He identified three degrees of talent: highest, middle and lowest.
1876 - "The History of Twins as a Criterion of Relative Strength, Nature and Nurture" - the twin and genealogical methods were introduced to clarify issues of inheritance of talent. Even then I realized that there are monozygotic and dizygotic. There is an unchangeable part of heredity, and there is a changeable part.
“Essay on Eugenics” - defines this science (deals with all influences that improve the quality of the race). It is necessary to educate the people.
Stage of qualitative characteristics.
Stage 2. - 1900 -1930 (stage of quantitative characteristics).
The work of Fisher, Wright and Pearson together with Galton gave rise to this stage - the genetics of quantitative traits.
Statistical methods are emerging. Psychodiagnostics is actively developing. Reliable methods for diagnosing zygosity of twins are emerging. A method is emerging for comparing separately grown monozygotic twins.
They are beginning to conduct research on the genetics of animal behavior.
Stage 3 - 1930 - 1960.
Psychogenetics of intelligence.
Measurement of psychogenetic research of mental defects, psychiatric diseases.
Faller, Thompson, "The Genetics of Behavior."
Stage 4 - 1960 - 90s.
Shifting the emphasis from psychogenetic research to research on temperament, personality traits, motor skills and psychophysiological functions.
Limitations of some methods were discovered (especially in the twin method).
Domestic psychogenetics.
Stage 1 - until 1917
Wolf - he was interested in the collection of freaks. He believed that freaks were beautiful creatures and were created by nature.
Freaks are extreme deviations from the norm, and by understanding them, one can establish the general principles of all development.
Two main questions.
- What can be passed on to offspring at birth?
- Can the internal and external improvements acquired through exercise be transferred?
Temperament, almost all diseases, predisposition to illness, human virtues, six-fingeredness can be transmitted.
Wolf made a lot of mistakes. I didn’t understand where hereditary information was stored.
“+” he foresaw that a lot of things are inherited.
What is acquired is also inherited.
Stage 2 - 1917 - 1930
Filipchenko Yu.A.
He was the first to receive a doctorate in genetics.
Tries to answer questions (from Wolf).
1916 - “Heredity”, what characteristics are inherited, but the answer is not given. Goes to eugenics (the science of improving the human race), the founder of which is considered to be F. Galton. “Eugenics is a good science and we should encourage the birth of children not only of gifted children, but of all.” Each parent must decide for themselves whether to give birth to a child with defects. They educated families if they had any abnormalities or abnormalities in their past.
Stage 3 - 1930 - 60s.
There was a defeat of genetics and the science of pedology was banned. Father for several decades. Genetics ceased to exist.
Kanaev "Twins"
Yudovich, Luria “Speech and the development of mental processes in a child.”
Stage 4 - since 1970
The beginning of systematic research in psychogenetics.
The first laboratory is being created - Ravich - Shcherbo (headed until 1993). Based on the laboratory of Teplov and Nebylitsyn.
Population studies were carried out in isolation wards in Dagestan and in villages in Turkmenistan.
Efroimson “Ethics of ethics and aesthetics.”
History of genetics.
Stage 1 - 1900 - 1930
Stage 2 - 1930 - 1953
Stages 1-2 - stages of classical genetics, neoclassicism.
Stage 3 - 1953 - to the present day - the era of molecular (synthetic) genetics.
G.I. Mendel (1865) - helped his parents in gardening and gardening.
At the age of 10 I was sent to study at a gymnasium (I left and came again due to lack of money). I started giving lessons and earning money.
Didn't finish university (because of money). My sister gave her money (for marriage).
He conducted his experiments in the monastery (at first he crossed rabbits, but he had to give up and began to work on peas - for 8 years, artificially pollinated flowers, counted by hand - as a result he discovered the laws of heredity. No one understood him.
Nothing worked with wheat.
1901 - 1903 - Friesian mutation theory.
1902 - 1907 - Wilson, Bovern - substantiated the chromosomal theory of heredity.
1906 - Betson - introduced the name genetics.
1909 - Johansen - introduced the concept; gene, genotype, phenotype.
1910 - 1925 - the chromosomal theory of heredity was created. Vavilov proposes and creates a gene bank.
The development of domestic genetics has been suspended.
1941 - incompatibility of mother and fetus due to the Rh factor.
1940 - 1953 - solving problems of human genetics.
1953 - discovery of the spatial model of DNA structure (Watson, Krieg, Wilkins).
1954 - proof of the role of infectious diseases in the formation of the human gene pool.
1956 - it was established that there are 46 chromosomes (Tio, Levan)
1959 - the cause of Down syndrome was established, as well as the role of the y chromosome in determining sex.
1970 - all methods for differential chromosome staining appeared.
1972 - a new industry is developed - genetic engineering.
In Western literature, most works use the term “behavior genetics”, and in Russian terminology the term “psychogenetics” is more adequate, because, firstly, the unit of behavior analysis is an act (S.L. Rubinstein, 1956, etc.) , which is not a trait in the genetic sense of the word, and, secondly, the traits studied in psychogenetics (IQ scores, temperament characteristics, etc.) are not “behavior” itself.
Psychogenetics test questions
Features of functional asymmetries in twins.
Genotype – environmental relationships in individual development.
Concepts, methods and models of age-related psychogenetics.
Age dynamics of genetic and environmental determinants.
Subject and tasks of psychogenetics.
History of the development of psychogenetics.
Variability. Definition of the concept.
Basic concepts of the theory of heredity.
Inheritance. Definition of the concept.
Genotype and phenotype.
Genotype, gene, allele.
Dominance. Definition of the concept.
Recessiveness. Definition of the concept.
Chromosomes. Karyotype.
Chromosomal aberrations.
The role of G. Mendel in the development of genetics.
Mendel's first law.
Mendel's second law.
Mendel's third law.
Non-Mendelian genetics.
DNA as the basis of heredity.
DNA structure.
Transcription. Definition of the concept.
Broadcast. Definition of the concept.
Types and structure of genes.
DNA mutations.
Natural selection.
Methods of psychogenetic research.
Geneological method.
Method of adopted children.
Twin method.
A variation of the twin method.
Psychogenetic studies of intelligence.
Verbal and non-verbal intelligence.
Temperament. Definition of the concept.
Psychogenetic studies of movement.
Motor tests.
Genetic psychophysiology. Subject of discipline and tasks.
Levels of analysis of brain genetics.
Electroencephalography as a research method.
Types of electroencephalography and their hereditary causes.
Functional asymmetry. Definition of the concept.
The role of heredity and environment in the formation of functional asymmetry.
Development of functional asymmetry in ontogenesis.
Normative and individual in the development of psychological characteristics.
Stability of psychological traits in ontogenesis.
Age aspects of psychogenetics.
Age aspects of genetic psychophysiology.
Mental dysontogenesis.
Psychogenetics
Psychogenetics is an interdisciplinary field of knowledge, borderline "between psychology (more precisely, differential psychology) and genetics; the subject of its research is the relative role and effect of hereditary and environmental factors in the formation of differences in psychological and psychophysiological characteristics. In recent years, the scope of psychogenetic research has also included individual development: both mechanisms of transition from stage to stage, and individual development trajectories.
In Western literature, the term “behavioral genetics” is usually used to refer to this scientific discipline. However, in Russian terminology it seems inadequate (at least in relation to humans). And that's why.
In Russian psychology, the understanding of the term “behavior” has changed, and quite dramatically. At L.S. Vygotsky’s “development of behavior” is actually a synonym for “mental development”, and, therefore, the laws established for specific mental functions are valid for it. However, in subsequent years, “behavior” began to be understood more narrowly, rather as a designation of certain external forms, external manifestations of human activity that have personal and social motivation.
S.L. Rubinstein wrote back in 1946 that it is precisely when Motivation moves from the sphere of things, objects, to the sphere of personal-social relations and acquires leading importance in human actions, “human activity acquires a new specific aspect. It becomes behavior in the special sense that this word has when they talk about human behavior in Russian. It is fundamentally different from “behavior” as a term in behavioral psychology, which is retained in this meaning in animal psychology. Human behavior contains as a defining moment the attitude towards moral norms.”
B.G. Ananiev considered the question of the relationship between “behavior” and “activity” in a different aspect, namely from the point of view of which of these two concepts is more general, generic. He believed that his decision could vary depending on the perspective from which he studied the person.
The task of psychogenetics- elucidation of not only hereditary, but also environmental reasons for the formation of differences between people according to psychological characteristics. The results of modern psychogenetic research provide information about the mechanisms of action of the environment to the same, if not greater, extent as about the mechanisms of action of the Genotype. In general terms, it can be argued that the main role in the formation of interindividual variability in psychological characteristics belongs to the individual (unique) environment. Its role is especially high for personality and psychopathological traits. Increasing emphasis in psychogenetic research is being placed on the relationship between family socioeconomic level or length of schooling with the results of children's intelligence tests. And even such formal characteristics as the parameters of the family configuration (number of children, serial number of birth, interval between births) turn out to be important for the individualization of the child - both in the cognitive and personal spheres.
As a result, the similarity of members of a nuclear family in terms of psychological characteristics stated in the study may have both genetic and environmental origins. The same can be said about the decrease in similarity with a decrease in the degree of relatedness: as a rule, in this case we are dealing with different families, i.e. We are talking about a decrease not only in the number of common genes, but also in different family environments. This means that a decrease in similarity in pairs of people related more distantly is also not evidence of the genetic determination of the trait under study: in such pairs the genetic commonality is lower, but at the same time the environmental differences are higher.
All this leads to the conclusion that family research by itself, without combining it with other methods, has a very low resolution and does not allow one to reliably “separate” the genetic and environmental components of the variance of a psychological trait. Although, when combined with other methods, for example with twins, family data make it possible to solve questions that are impossible to solve without them (for example, to clarify the type of hereditary transmission - additive or dominant), or to control environmental variables (for example, the general family and individual environment, the effect twinhood).
Methods of psychogenetics
METHODS OF PSYCHOGENETICS (from the Greek psyche-soul, genos-origin) - methods that allow us to determine the influence of hereditary factors and the environment on the formation of certain mental characteristics of a person.
The most informative is twin method. It is based on the fact that monozygotic (identical) twins have an identical genotype, dizygotic (fraternal) twins have a non-identical genotype; Moreover, members of twin pairs of any type must have a similar upbringing environment. Then the greater intrapair similarity of monozygotic twins compared to dizygotic twins may indicate the presence of hereditary influences on the variability of the trait being studied. A significant limitation of this method is that the similarity of the actual psychological characteristics of monozygotic twins may also have a non-genetic origin.
Genealogical method- study of similarities between relatives in different generations. This requires accurate knowledge of a number of characteristics of direct relatives on the maternal and paternal lines and coverage of the widest possible range of blood relatives; It is also possible to use data from a sufficient number of different families to reveal similarities in pedigrees. This method is mainly used in medical genetics and anthropology. However, the similarity of generations in terms of psychological characteristics can be explained not only by their genetic transmission, but also by social continuity.
Population method allows you to study the distribution of individual genes or chromosomal abnormalities in human populations. To analyze the genetic structure of a population, it is necessary to examine a large group of individuals, which must be representative, that is, representative, allowing one to judge the population as a whole. This method is also more informative when studying various forms of hereditary pathology. As for the analysis of the heritability of normal psychological traits, this method, taken in isolation from other methods of psychogenetics, does not provide reliable information, because differences between populations in the distribution of a particular psychological trait can be caused by social reasons, customs, etc.
Adopted children method- comparison of similarities on any psychological basis between the child and his biological parents, on the one hand, and the child and the adoptive parents who raised him, on the other.
The methods require mandatory statistical processing specific to each method. The most informative methods of mathematical analysis require the simultaneous use of at least the first two methods.
The concepts of genotype and phenotype - very important in biology. The totality of all the genes of an organism constitutes its genotype. The totality of all the characteristics of an organism (morphological, anatomical, functional, etc.) constitutes a phenotype. Throughout the life of an organism, its phenotype may change, but the genotype remains unchanged. This is explained by the fact that the phenotype is formed under the influence of the genotype and environmental conditions.
The word genotype has two meanings. In a broad sense, it is the totality of all the genes of a given organism. But in relation to experiments of the type that Mendel performed, the word genotype refers to the combination of alleles that control a given trait (for example, organisms can have the genotype AA, Aa or aa).
The term "genotype" was introduced into science by Johannson in 1909.
(from the Greek phaino - I reveal, reveal and typos - imprint, form, sample) - result the interaction of all the genes of an organism with each other and various environmental factors, a set of characteristics inherent in a given organism.
The term "phenotype" like genotype, it is used in two senses. In a broad sense, it is the totality of all the characteristics of an organism. But in relation to monohybrid crossing, the word phenotype usually denotes the trait that is studied in this crossing, for example, a tall plant has one phenotype, and a dwarf plant has another.