Behavioral genetics, a branch of behavioral science that is based on the laws of genetics and studies the extent and manner in which differences in behavior are determined by hereditary factors. The main methods for studying genetic behavior in experimental animals are selection in combination with inbreeding (inbreeding), with the help of which the mechanisms of inheritance of forms of behavior are studied; in humans, statistical and genealogical analysis in combination with twin and cytogenetic methods. (5).

The dependence of behavior on hereditary factors - gene management and control of behavior - is studied at various levels of the organization of living things: in biocenoses, populations, communities, at the level of the organism, as well as at the physiological (organ, tissue, cell) and molecular levels. Research on the genetics of behavior has significant significance for the study of individual differences in higher nervous activity and identifying the relative role of congenital and individually acquired characteristics of behavior, for explaining the role of genetically determined characteristics of animal behavior in a population (for social animals - in a herd, flock, etc.), as well as for creating experimental models of nervous diseases.

Behavioral genetics is a relatively young field of knowledge, which took shape about half a century ago at the intersection of such disciplines as genetics itself, developmental biology and a complex of behavioral sciences, including psychology, ethology and environmental physiology. The task of this new direction was to study the ontogenesis of a broad class of biological functions of the body, called “behavior” and providing essentially two-way communication between the individual and his surrounding ecological and social environment. The global nature of this task in itself was the reason that the sphere of interests of behavioral genetics soon became involved in such widely separated areas of science and practice as endocrinology and psychiatry, biochemistry and pedagogy, neurophysiology and linguistics, anthropology and breeding of farm animals. In addition, since it has long become obvious that behavior is one of the most important factors in the evolutionary process, the genetics of behavior in recent years has become more and more closely linked with evolutionary teaching, becoming an integral part of modern evolutionary biology.

Genetic analysis of animal behavior

Genetic research in humans has a number of understandable limitations. In this regard, studies of the genetic basis of behavior in animals are of interest. Here you can use selection methods, obtaining inbred lines, modern methods of genetic engineering, selectively turning off certain genes, causing mutations, etc. Inbred lines obtained through long-term inbreeding (at least 20 generations) represent animals identical in genotype, therefore all differences that can be observed among animals of the same line are associated with environmental influences.

Genetics of insect behavior

Let us give an example of genetic analysis of behavior, which is quite often discussed in educational literature. We'll talk about bees and a disease called American larval rot. There is a line of bees that are resistant to this disease because if the disease occurs, the bee larvae will immediately unseal the cell they are in and remove it from the hive. This prevents the spread of the disease, and resistance to it is associated with characteristic behavior! When bees that are resistant to the disease are crossed with those that are not resistant, first generation hybrids (F1) are obtained that do not clean the hives. It is clear from this that the allele or alleles causing this type of behavior are recessive. The first generation F1 hybrids are again crossed with resistant bees (the so-called analytical crossing - with recessive homozygous individuals). As a result, the offspring exhibit four variant phenotypes in a 1:1:1:1 ratio. These are the options:

– bees open the cells and remove the affected larvae;

– open the cells, but do not remove the affected larvae;

– do not open the cells, but remove the affected larvae if the experimenter opens the cell;

– do not open the cells, do not remove the affected larvae.

Thus, it is obvious that this rather complex behavioral act is controlled by genes at only two loci. One allelic gene determines the actions of opening the cell, the other is associated with the removal of the affected larva.

In this case, it is impressive that quite complex actions can be controlled by just one gene.

Fruit flies, Drosophila flies, which have been a favorite target of geneticists for many years, have a huge number of mutations affecting behavior. Yes, mutation dunce leads to disruption of the ability to develop conditioned reflexes. There are several known mutations that somehow impair learning. It is important that all these defects are associated with impaired metabolism of so-called second messengers (primarily cyclic AMP), which play an important role in intracellular signaling and synaptic plasticity.

There are mutations that lead to high and low sexual activity, to the avoidance of certain odors, changing motor activity, even to the point that there is a mutation that determines how the Drosophila folds its wings - right over left or vice versa.

Sometimes there are examples of very specific behavioral deviations. So, with mutation fru(from fruitless– infertile), the following disturbances in sexual behavior are observed in males: they do not court females, but only court males homozygous for this mutation, and stimulate normal males to court themselves. The result was something like a model for the formation of homosexual behavior.

In general, one gets the impression that most behavioral acts in Drosophila are genetically predetermined in every detail.

Animal learning studies

One of the most important properties of animal behavior is the ability to learn. Animal research provides an opportunity to conduct breeding experiments. Tryon was one of the first to conduct such an experiment on rats. He carried out selection based on the learning ability of animals, which had to find the correct path to feeding placed in a complex 17-dead-end maze. Animals that were good and poorly trained were selected and subsequently crossed only with each other. Regular selection gave a very quick result - starting from the eighth generation, the learning indicators of “smart” and “stupid” rats (the number of erroneous runs in the maze) did not overlap. Selection was carried out until the 22nd generation, as a result of which two groups of rats were obtained - well trained ( bright) and bad – ( dull). Under the same growing and testing conditions, differences between these groups are due only to differences in genotype.

Subsequently, many strains were obtained, especially in mice, differing in their ability to perform various forms of learning. Similar lines were selected for their ability to learn in the T-maze, for learning active and passive avoidance, and swimming in the Morris water test. Sometimes the task an animal performs is quite complex. For example, strains of mice were obtained that were good and bad at learning the food-procuring motor conditioned reflex. The mice were reinforced when they jumped in response to a sound or light stimulus onto different shelves. In this case, some community patterns can be noted:

1) there is usually a large variation of the trait in the source population;

2) Although the selection response can appear very early, and the difference between lines is detected after 2–3 generations, it takes much more generations (about 10–20) for stable significant differences between lines to appear.

The high spread of initial values ​​of the trait and the gradual development of the selection response are evidence of the polygenic nature of the trait. In other words, the manifestation of this trait in the phenotype depends on a relatively large number of genes. The same is true for most mammalian behavioral traits.

There is another problem associated with selection experiments. Selection is carried out when testing a specific task. Naturally, the question arises: to what extent does the ability to solve this problem correlate with the ability for other types of learning? There is no clear answer to this question.

For example, when they began to study in more detail the ability to learn in general on lines of rats obtained by Tryon ( bright And dull), it turned out that those who were well trained ( bright) learn food-procuring behavior faster, and rats dull in turn, demonstrate better performance in defensive reaction tasks. Thus, here the problem of learning can be transferred to the plane of motivational mechanisms. It is known that motivation can have an extremely strong impact on learning outcomes.

It turns out that the rat line bright are more motivated by hunger, while rats dull are more motivated by fear in threatening situations. Just like motivation, the success of learning can be influenced by sensory abilities, the level of motor activity, and the emotionality of animals. Accordingly, genes that influence the activity of these qualities can have an impact on learning.

However, some lineages also show differences in more general learning abilities. So, mouse lines DBA/2J learn better than animal lines C.B.A., which is confirmed in a number of tests: during food reinforcement in the maze, in the shuttle chamber during the development of a conditioned reflex reaction of active avoidance, during operant learning. This means that there are certain genetically determined properties of the nervous system that affect the ability to implement various types of learning. The list of mutations that impair learning and memory in mice is rapidly expanding.

Table 1. Mouse genes localized on certain chromosomes and playing an important role in learning and memory

Differences in memory characteristics were also noted in Tryon's rats, which certainly affected the test results. So, it turned out that rats have lines bright consolidation occurs faster - strengthening of memory traces, their transition into a stable form. You can resort to influences that disrupt short-term memory, for example, using a special form of electric shock that causes amnesia. It turned out that already 75 s after training, electroshock amnesia cannot be induced in rats of the line bright, whereas on the rat line dull The electroshock procedure still has an effect.

Different speeds of consolidation appear to determine differences in the success of forming orientation skills in a maze. What happens if rats line dull will you be given enough time to memorize? Studies have shown that when the intervals between trials were 30 s, rats bright learned much faster than line rats dull, as it should have been. But when the interval was increased to 5 minutes, the difference in learning between the lines decreased significantly. If the rats were given only one trial per day, the learning performance of both strains became identical. The speed of skill acquisition and the speed of consolidation can be determined by different mechanisms!

An important conclusion: selection of learning conditions can reduce or even eliminate differences in genetically determined abilities.

Currently, a number of mouse strains have been obtained that differ sharply in the speed of memory consolidation. There is a line ( C3H/He), in which learning is possible only through continuous training. There is a line ( DBA/2J), in which training, on the contrary, is much more successful when the intervals between individual training sessions increase. And finally, the line (BALB/c) was introduced, for which the nature of the intervals between experimental sessions does not affect the learning results. This approach thus creates unique opportunities for studying memory mechanisms.

Another area of ​​animal research is to elucidate the influence of the environment on the formation of behavioral properties. Let's go back to line rats again bright And dull. You can conduct an experiment to raise these rats in different conditions. One group (control) is grown under normal vivarium conditions. For the other, an “enriched” environment is created - large cells with painted walls, filled with various objects, mirrors, swords, ladders, stairs, tunnels. Finally, the third group is provided with an “impoverished” environment, where the influx of sensory stimuli is severely limited and the possibilities for search and exploratory activity are limited. In graph 1, the enriched environment is designated as “good” conditions, the depleted environment as “bad”. Normal conditions correspond to the control group.

Graph 1. Results of training in a maze of lines of “smart” and “stupid” rats raised in deteriorated, normal and improved conditions. (15).

The results of the control group correspond to expectations - rats of the line bright when learning in a maze, they make much fewer mistakes compared to rats of the line dull. However, for rats raised in an enriched environment, this difference practically disappears, mainly due to a sharp decrease in errors in the “stupid” strain of rats. In the case of rearing in a depleted environment, the difference between the two lines also disappears, and this time mainly due to a sharp increase in the number of errors in the “smart” line of rats.

Here we touch upon a very important problem - the existence of powerful mechanisms of plasticity of the nervous system that are capable of compensating for very significant defects. Numerous studies on raising rats in an enriched environment have shown that relatively quickly - within 25-30 days - very significant morphological differences arise at the level of the cerebral cortex. Animals kept in an enriched environment have a thicker cortex, larger neuron sizes, and a 10–20% increase in the number of dendritic processes per neuron. All this leads to a 20% increase in the number of synapses per neuron. Ultimately, we are talking about billions of new synapses, which dramatically increases the capabilities of the nervous system. Particularly important is the fact that this plasticity potential is maintained almost all the time. Experiments on adult animals led to similar results. Similarly, an enriched environment has an impact on a child’s development.

Video: About the influence of genetics on behavior and character.


BEHAVIOR GENETICS- a branch of genetics devoted to the study of patterns of hereditary conditioning of functional manifestations of the activity of the nervous system. The main task is to describe the mechanisms of implementation of genes in behavioral traits and highlight the influence of the environment on this process.

Along with other research methods, the genetic selection method is used here, thanks to which the properties of the nervous system and behavioral characteristics can be purposefully changed.

Each heritable behavioral trait usually has a complex polygenic character. Animals from lower levels of the evolutionary ladder (insects, fish, birds) are characterized by low variability in innate, instinctive actions determined by genotype. With evolutionary development, the process of formation of conditioned reflexes becomes increasingly important, and the genotype determines phenotypic variability less and less.

Information important for adaptation is not only acquired in one’s own experience, but can be transmitted from parents to offspring through direct contacts, due to imitative conditioned reflexes.

Data obtained in the genetics of behavior are of particular importance for the study of human nervous activity in pathologies: often mental retardation and mental illnesses are hereditary and associated with genetic disorders.

BEHAVIOR GENETICS(English)

Behavioral genetics) is a section of genetics that studies the patterns of hereditary determination of the structural and functional characteristics of n. With. G. p. allows us to understand the nature of the hereditary transmission of behavioral characteristics; reveal the chain of processes unfolding in ontogenesis leading from genes to traits; isolate the influence of the environment on the formation of behavior within the potential capabilities specified by the genotype.

Using the genetic selection method, the properties of n. s.and behavioral features m.

b. directionally changed. The inheritance of differences in behavioral traits is, as a rule, complex polygenic in nature.

It has been experimentally shown that the species stereotype of animal behavior has a very strict hereditary conditionality.

Low variability of innate, instinctive acts is especially characteristic of animals standing at lower levels of the evolutionary ladder - insects, fish, birds, but even in insects the behavior is m.

b. modified due to the development of temporary connections. Moreover, behavior is not a simple result of evolutionary changes; it plays an active role in evolution, since through behavioral adaptations the effect of selection is manifested in the animal population and the regulation of its structure and numbers is ensured.

Hereditary information from parents to descendants can be transmitted on the basis of direct contacts, through the development of imitative conditioned reflexes and other ways of perceiving and transforming information (i.e.

n. signaling heredity).

Of particular importance for genetic research is the study of human nervous activity—in normal and pathological conditions. Often mental retardation and mental illnesses have a hereditary etiology associated with genetic metabolic disorders, changes in the number and structure of chromosomes, etc.

disorders of the genetic apparatus.

behavioral genetics

See Psychogenetics. (I. V. Ravich-Scherbo.)

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Lecture 3. 1. Innate forms of behavior

1. Innate forms of behavior

2. Acquired forms of behavior

The adaptation of animals, in the processes of evolution, to relatively constant phenomena and those that are periodically repeated in the external environment, has developed in them genetically fixed, innate forms of behavior.

At the same time, adaptation to fickle, unstable environmental conditions forms in each generation of animals dynamic forms of behavior that are acquired throughout ontogenesis.

Congenital Behaviors

At different stages of evolution, the following innate adaptive reactions can be distinguished: taxis, reflexes and instincts.

Taxis are the simplest form of behavior that determines the interaction of an organism with the external environment in unicellular and multicellular organisms.

Taxis in ethology is called oriented (directed) movement, which is connected with some complex of fixed actions.

For example, when a greylag goose rolls a deflated egg toward the nest, it performs lateral movements that are designed to hold the egg under its beak. These directed movements represent taxis. At the next stages of evolution, the role of taxis sharply decreases and they are replaced by other, more advanced adaptation mechanisms.

Reflexes are also a type of adaptive behavior. In this case, we consider an innate unconditioned reflex reaction, which serves as one of the main types of adaptation in the animal world.

For example, a chicken that has just hatched from an egg begins to peck, and a calf begins to suck.

Instinct (from the Latin “instinctus” - impulse) is a set of innate stereotypical acts of behavior characteristic of individuals of a given species under certain conditions.

Examples include food, imitation, herd, play (in young animals), and migration.

Each such instinct can also include simpler instinctive acts. For example, releasing chicks from the nest, pecking grain, babies sucking milk, and tentatively exploratory reactions.

Instinctive behavior, like all other forms of behavior, has a certain direction - the preservation and development of the organism in conditions characteristic of the life of this species of animal.

According to the teachings of I.P. Pavlov, in the physiological understanding, instincts are chains of complex unconditioned reflexes fixed by evolution, which include compelling and reinforcing reflex links.

In other words, the most complex unconditioned reflexes (for example, nest-building, play, etc.) are represented not by one reflex arc, but by a whole complex of unconditioned reflex reactions.

This complex includes all genetically determined mechanisms necessary for the formation of appropriate acts of behavior: the mechanism of formation of metabolic needs, the mechanism of biological motivations, the mechanism of foresight and evaluation of results, the mechanism of achieving goals (K.V. Sudakov).

Obviously, all mechanisms cannot be formed at the time of birth. Some of them (for example, sexual motivation) are formed in the processes of ontogenesis, as morphofunctional and endocrine systems form and mature.

Coordinated movements of the wings of birds during flight do not immediately arise: this habit depends on learning.

To student I.P. Pavlova to academician L.O. Orbeli has a reasoned concept of postnatal maturation of unconditioned reflexes under the influence and interaction with conditioned ones. For example, building a nest in a rat is an innate chain reflex, but it can be destroyed by raising the rat in a cage with a slatted floor, where the animals’ attempts to collect materials for building a nest have previously ended in failure (P.V.

Simonov). The innate chain reflex of hatching eggs does not manifest itself when chickens are kept in cages.

In our time, the view of the exclusively genetic nature of instincts has changed. Genes cannot determine the course of ontogenesis regardless of the environment.

So, be - what types of behavior are the result of genetic and environmental interactions.

Instinct also needs “training,” which is illustrated by the presence of so-called imprinting.

Instead of the term “instinct,” the expression “innate forms of behavior” is now predominantly used, emphasizing only their relative independence from environmental influences.

In the implementation of acts of behavior based on the innate reactions of animals, the structures of the diencephalon (hypothalamus) and the limbic system play an important role. Thanks to them, behavioral reactions are adaptive, adaptive in nature and are able to maintain biochemical and metabolic homeostasis.

Acquired Behaviors

Acquired forms of behavior include learning and mental activity.

Learning is the process through which life experiences influence the behavior of each individual, and allows animals to develop new adaptive reactions taking into account past experiences, as well as change those reactions that turned out to be non-adaptive.

At the same time, the behavior of animals becomes more flexible and adaptive. As the research of I.P. Pavlov showed, the basis of learning is the formation of conditioned reflexes.

The conditioned reflex is the main form of learning. A conditioned reflex is an adaptive reaction of animals that occurs through the formation of temporary nervous connections between two excitation centers in the cerebral cortex: the center of conditioned and the center of unconditioned stimuli.

The conditioned reflex is a functional unit of activity in the higher parts of the brain.

Two types of conditioned reflexes can be distinguished: the first type is the classical Pavlovian conditioned reflex, the second is the operant (instrumental) conditioned reflex.

Both of them are reproduced in laboratory conditions. In the first case, the animal’s reaction to a conditioned stimulus recreates an unconditioned reflex (secretory or motor), and in the second case, movement, which is a necessary condition for reinforcement. For example, the call is not reinforced with food every time, but only if the animal presses the lever. An example of an instrumental conditioned reflex is the process of drinking water from a drinking bowl.

The animals press the valve with their muzzle, water flows into the drinking bowl and the animals drink. In this reflex there are causal-hereditary relationships, and the fact of unconditional reinforcement depends on the animal itself.

Conditioned reflex learning of both types is associative learning, i.e. such that it arises as a result of the formation of connections in the brain, which can be modified or destroyed when the living conditions of the individual change.

There are also non-associative forms of learning, which include: habituation, latent learning, imitation, trial and error, imprinting, insight.

addictive- the simplest form of behavior - it does not consist in identifying a new reaction, but in losing the one that existed before.

If animals are offered a stimulus that is not accompanied by reinforcement or punishment, then gradually the animals stop responding to it.

For example, birds gradually stop paying attention to a scarecrow that forces them to fly away when it is first placed on the field. Phenomena similar to addiction are found in any group of animals, starting with the simplest, all typical properties of addiction can be found at the level of individual neurons and neuromuscular connections.

Habituation is one of the important processes of adaptation of animal behavior to living conditions. Habituation will also play an important role in the development of behavior in young animals, which are often threatened by various predators (they quickly learn not to respond to foliage when they are moved by the wind and other neutral stimuli).

The innate pecking reaction in newly born chicks is initially directed at any small object, but then habituation to unnecessary objects occurs.

Latent learning according to Thorpe's definition, it is the formation of a connection between indifferent stimuli or situations without explicit reinforcement.

Latent learning, in its natural form, is often the result of animals' exploratory activity in a new situation. In the process of exploring conditions, animals accumulate information about them.

2.10. Behavioral genetics

The life of a small animal or bird when a predator attacks it depends on detailed knowledge of the geography of the area where it lives. Information about the environment can later be used in the processes of searching for food or a sexual partner.

Numerous insects carry out a special “reconnaissance flight” during which they record the position of the site relative to the Sun and the outskirts.

Thus, bees during a reconnaissance flight, which lasts 1-2 minutes, remember the new location of the hives.

Imitation (inheritance)- one of the forms of training.

The learning of species songs by birds is based on imitation. Through imitation, young farm animals learn to master many necessary exercises and habits, for example, the ability to graze. When cows are kept in boxes, a newborn calf, imitating a cow, quickly gets accustomed to eating roughage.

Trial and error method– a complicated reflex in which problems are solved as a result of a blind search.

This type of learning was studied by E. Thorndike through the use of a variety of “problem chests”. The latter were a cage that could be opened from the middle only by pressing a lever or pulling a ring. A cat placed in such a cage makes an attempt to escape; it runs around the cage without stopping until after some time it accidentally tugs at the ring. After the second and third attempts, the cat concentrates its attention on the lever, and as soon as it is locked, it rushes to the ring and fiddles with it.

Trial and error learning is often observed in changes in animal behavior that involve searching for food, storage, or a sexual partner.

As a rule, this process is accompanied by the formation of conditioned reflexes of the first order, since both new stimuli and new behavioral reactions must be remembered.

Trial and error, reliably, is the category that is most suitable and to which the formation of new motor exercises can be attributed. Young mammals and birds, for example, improve the coordination of their movements through training, playing with their parents and among themselves.

Rice. 6. The goslings are watching Konrad Lorenz.

Imprinting was first described by K. Lorenz in 1937 in birds. Imprinting is also observed in sheep, goats, deer, horses and other animals, whose babies are able to move immediately after birth. Imprinting is observed in the reactions of newborn animals following a moving object. Imprinting is a special form of learning that has much in common with conditioned reflex learning, although it is tuned not to individual, but to species characteristics. It is formed only in the early stages of postembryonic development. Thus, in his experiments, Lorenz forced broods of goslings, who mistook him for their mother, to follow him (Fig. 6).

Similar phenomena are observed in mammals. The human-raised lambs follow her and show no curiosity about other sheep. Scott and Filler summarized the results of substantial research in dogs. They found that between three and ten weeks of age, dogs have a sensitive period during which puppies form normal social interactions.

Puppies isolated for more than 14 weeks do not subsequently respond to their relatives, and their behavior is completely abnormal.

Insight- the most important degree of acquired behavior.

This behavior is based on understanding. It occurs predominantly in the most developed representatives of chordates - primates. A classic example of insight in animals is provided by Keller's early experiments on chimpanzees. When several bananas were clinging very high, and the monkeys were unable to reach them, they began to stack boxes one on top of another, or inserted sticks one into another so that they could climb higher and knock the bananas to the ground.

More often, they arrived at such a decision entirely unexpectedly, although they used previous experience of playing with boxes and sticks (latent learning), and the monkeys needed a significant period of trial and error to build a stable pyramid of boxes. Elements of mental activity often appear in the behavior of anthropoid apes and other primates. Numerous dog owners give examples of their dogs doing smart things.

Insight can be seen as a manifestation of the ability to think creatively.

Thinking- the highest form of behavior that dominates in a person. Higher animals have a proven presence of elementary mental activity. An example would be insight. Sometimes, after a series of unsuccessful attempts and a pause, which then comes, animals unexpectedly change the tactics of their behavior and solve the problem. So, in the brains of the animals, an assessment of previously carried out attempts occurred, and adjustments were made to the plan of further actions.

In higher animals, elements of mental activity exist and develop in evolutionary terms. This accounts for the ability of animals to solve complex problems. So, in the animals’ brains an assessment was made of earlier attempts and adjustments were made to the plan for further actions.

In higher animals, elements of mental activity exist and develop in evolutionary terms. This involves animals solving complex problems. The considered forms of complex behavior - learning and thinking - arise at the highest stages of evolution.

Learning becomes dominant in mammals. Their behavior is determined by reactions that are innate and acquired as a result of learning.

Lecture 3

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Variation due to genetic factors

Variation due to genetic factors is complex, but if it is significant and known, it can be used to calculate the possible gain for certain tree characteristics.

Genetic variation can be divided into two main components: additive And non-additive. If we imagine this in statistical terms, then genetic variance consists of additive and non-additive variance components.

The additive component of variance is the variability caused by the combined action of alleles of all gene loci that affect the characteristic. Non-additive genetic variation can in turn be divided into two parts: dominant And epistatic. Dominant variance is caused by the interaction of certain alleles located in one gene locus, while epistatic dispersion is caused by the interaction between genes of different loci.

This concept will be discussed in more detail later.

Here it is enough to note that the additive part is one of the most important in programs for selective improvement of populations.

Non-additive variation can be used in other, more specialized programs that involve making specific crosses or using vegetative propagation for commercial purposes. In most genetic breeding improvement programs, non-additive genetic variation usually receives less attention because the additive portion of the genetic variance can be more easily exploited.

Most characteristics of economic importance are, to one degree or another, under the control of the additive component of genetic variability (V.

Zobel, J. Talbert, 1984). This is important because additive variance can be successfully used in simple breeding systems. The qualitative characteristics of wood, such as density, straightness of the trunk and others, are determined to a greater extent by additive dispersion than growth characteristics.

Although growth performance is controlled to some extent by additive genetic influences, it is also significantly influenced by the nonadditive variance associated with it. Therefore, any breeding program must include testing of the progeny of selected phenotypes to determine the true genetic value of the trees.

The response to selection for characteristics with significant non-additive variance, such as height, is significantly less satisfactory than the response to selection for quality characteristics, which are usually under stricter genetic control of the additive component of variance.

With regard to the characteristics of adaptation, it can be noted that this question has not yet been fully clarified.

However, available evidence favors inheritance of these characteristics in an additive manner. This suggests that any outstanding gains obtained for the improved characteristics of trees that grow satisfactorily in extreme or sub-extreme habitat conditions can be retained.

By selecting trees with outstanding characteristics that grow better in these conditions, and then using their seeds, one can expect to afforest such areas with trees with the desired economically important traits.

Pest resistance includes both additive and non-additive variance depending on the insect and tree species. But usually good results are possible when using the additive part of genetic variability in breeding programs.

The above principles should be used by breeders at the beginning of their work on a particular breeding program.

The first stages of work should involve determining the amount and type of variation in source natural or cultivated populations so that they can then be used in an intelligent manner.

Section 1. General issues of behavioral genetics.

Controlling environmental influences allows for better use of genetic variation.

To identify and use genetically determined variability, certain crossing or mating systems are most often used (matting systems). The type of crossing system within a species has the main influence on the variability of the studied samples.

Cross pollination (outcrossing), which is most characteristic of most species of forest woody plants, as a rule, produces highly variable (heterozygous) populations in genetic terms.

In cross-pollination, different genotypes successfully hybridize with each other, and only a small proportion of crosses occur between female and male organs of the same plant or between closely related individuals.

If the latter occurs, i.e., pollen from a tree or a given genotype pollinates its own female flowers, we speak of self-pollination (selfmg). The same thing happens if pollination occurs between ramets of the same clone.

Even if the ramets (grafts, root suckers, etc.) are separate plants, they are genetically identical.

Therefore, when creating forest seed plantations, care should be taken that grafting trees (ramets) of the same clone are not planted in close proximity to each other.

It should be noted that cross systems support a high degree of genetic variation, while in selfing systems genetic diversity is significantly reduced.

As a rule, growth vigor also decreases significantly when inbreeding occurs, i.e., as if there is a return from the hybrid to the original growth vigor.

This or that degree of relationship is characteristic of natural plantings. For this reason, it is recommended to take only one selected best tree from a stand to create forest seed plantations in one place.

Degrees of relationship can be very diverse. For forest woody plants, little is known about the effects of siblings or other inbreeding.

However, their adverse effects have been well studied in crop plants and are therefore recommended to be avoided. The most common phenomenon is a decrease in sperm production, although there were exceptions when during the mating of half-sibs and even full-sibs such a phenomenon was not observed. But what was common was not only a decrease in seed production, but also a decrease in germination during self-pollination.

When viable seedlings were obtained, they often had poorer growth (Ericsson et al, 1973 - cited by B. Zobel, J. Talbert, 1984). The unfavorable consequences of self-pollination were noted even earlier (A. S. Yablokov, 1965; E. Romeder, G. Shenbach, 1962, etc.; see also chapter).

The results of studying self-pollination in various species of coniferous and deciduous trees showed that the following consequences may occur (B. Zobel, J.

Talbert, 1984; Yu.N. Isakov, V.L. Semerikov, 1997, etc.):

1. No healthy seeds are formed.

2. Seeds are formed, but they do not form shoots.

3. The seeds are viable, but the seedlings are abnormal and often live only a short time and then die.

4. Seedlings survive, but they are small, weak, often with yellowed leaves and slow growing. Some of them can be diagnosed and removed at the nursery stage, before planting in a permanent place.

Seedlings grow more slowly than normal trees, but this is not noticeable enough to remove them at the nursery stage. Their further cultivation is undesirable, since they produce less wood than seedlings obtained from cross-pollination.

6. Seedlings grow as well, and sometimes even better, than those obtained from cross-pollination. Self-pollinating trees, the offspring of which grow as well as those from cross-pollination, are very rare.

All this suggests that when creating forest seed plantations, it is necessary to first study the source material and the possibility of using it in cross-pollination or self-pollination systems.

The use of inbred lines, subsequently cross-crossed, has been proposed as a breeding system.

This method is widely used in agriculture. However, it has been little practiced in breeding programs for forest tree species for several reasons: low seed productivity of self-pollinators, low vigor of inbred offspring, and a significant decrease in wood supply in breeding populations.

In general, based on the materials in this section, it should be noted that genetic variability, a very important aspect of breeding programs, can be significantly increased through intralocus and interlocus interactions, mutations, migrations and other evolutionary factors.

These phenomena will be discussed in more detail in the subsequent presentation.

Some traits are determined by single genes, but most human characteristics depend on many genes, that is, they are polygenic. Traits such as intelligence, height, and emotionality cannot be classified into clearly defined categories; they are constantly changing. Most people are neither dull nor brilliant; intelligence extends very widely, and most people are somewhere in the middle of its space. Sometimes a specific genetic defect can lead to mental retardation, but in most cases, a person's intellectual abilities depend on many genes that influence the factors underlying various abilities. Of course, what happens next to this genetic potential depends on environmental conditions (Plomin, Owen & McGruffin, 1994).

Selective breeding. One of the methods for studying heritable characteristics in animals is selective breeding. Animals with strong or weak manifestations of one or another characteristic are crossed with each other. For example, when studying the inheritance of learning ability, female rats that learn the maze poorly are crossed with males that are also bad at it, and females that learn well are crossed with the same males. The offspring from this cross are tested in the same maze. Based on the results obtained, the best individuals are re-crossed with the best and the worst with the worst. (To ensure that environmental conditions remain unchanged, the offspring of “stupid” mothers are sometimes given to be raised by “smart” mothers; in this way, it is genetic endowment that is tested, and not the adequacy of maternal care). After a few generations, you can get “smart” and “dumb” breeds of rats (Fig. 2.21).

Rice. 2.21.

Average error rates in “smart” and “stupid” rats selected for their ability to navigate a maze (after Thompson, 1954).

Selective breeding has been used to test the inheritance of a range of behavioral characteristics. For example, dogs were selected to have their offspring either excitable or apathetic, roosters to be aggressive and sexually active, fruit flies to be more or less attracted to light, and mice to be more or less attracted to alcohol. If a characteristic is influenced by heredity, then it can be changed through selection. If selection does not affect this characteristic, then the latter is determined mainly by environmental factors (Plomin, 1989).

Twin studies. Since, for ethical reasons, breeding work cannot be carried out on humans, one can instead look for similarities in behavior between individuals in related relationships. Some characteristics often run in families. But family members are not only related genetically, they also share a common environment. If musical talent is widespread in a family, it is impossible to say whether this is explained by hereditary ability or whether parental attention to music was more influential. The son of an alcoholic father is more likely to develop alcoholism than the son of a non-alcoholic father. What plays a leading role here: genetic tendency or environment? In an attempt to answer such questions, psychologists have turned to the study of twins.

Identical twins develop from the same fertilized egg and therefore share the same heredity; they are also called monozygotic because they come from a single zygote, or fertilized egg. Consanguineous twins develop from different eggs and are no more genetically similar than ordinary siblings; they are also called dizygotic, or two-egg. Consanguineous twins are approximately twice as common as identical twins. Comparative studies of identical and related twins help disentangle environmental influences from hereditary influences. Identical twins are more similar in intelligence than related twins, even if the twins were separated at birth and raised in different homes (see Chapter 13). In addition, identical twins are more similar than related twins with respect to some personality traits and susceptibility to the mental illness schizophrenia (see Chapter 15). Twin studies have proven to be a very useful method for investigating genetic influences on human behavior.

Molecular genetics of behavior. In recent years, some scientists have suggested that certain human traits, such as certain aspects of personality, are influenced by specific genes, which scientists believe act on particular neurotransmitter receptors (Zuckerman, 1995). Most studies of this type identify family members who possess a particular psychological trait and compare them with other family members who lack the trait. Using molecular genetics methods, researchers try to discover genes or chromosome fragments that correlate with the presence of the psychological trait being studied. Thus, there have been reports that a combination of traits known as “novelty seeking” (that is, the tendency toward impulsive, exploratory, and hot-tempered behavior as measured by personality scales) is associated with a gene that controls the dopamine D4 receptor (Benjamin et al. 1996).

In some cases, this type of analysis was carried out when studying very specific behavioral traits. In particular, we have already mentioned that sons of alcoholic fathers are more likely to become alcoholics themselves than randomly selected individuals. It has recently been reported that sons of alcoholics also release greater amounts of endorphin (a naturally occurring opiate neurotransmitter associated with reward) when drinking alcohol than other people (Gianoulalis, Krishnan, & Thavundayil, 1996); this suggests that there may be a biological predisposition to alcoholism.

However, such analysis can sometimes be misleading and should be treated with caution. For example, the claim has been made that the dopamine D2 receptor gene is found only in heavy alcoholics and thus represents the genetic basis of alcoholism. Further studies of this gene have shown, however, that it is also found in individuals who use many other forms of pleasure, and may be associated with drug abuse, obesity, compulsive gambling and other forms of "compulsive behavior" (Blum, Cull, Braveman & Comings, 1996).

Our understanding of the role of this gene and its relationship to behavior has clearly changed in the years since its discovery, and may change again as new data become available. This indicates the need to await further confirmation before concluding that a genetic basis for certain forms of behavior has been discovered. In some cases, what seemed like an obvious genetic explanation later turned out to be untrue.

The influence of the environment on the action of genes. The hereditary potential of an individual entering life is greatly influenced by the environment with which he encounters. We will return to explaining this interaction in subsequent chapters, but for now we will limit ourselves to two examples. The predisposition to developing diabetes is hereditary, although the exact mechanism of transmission is unknown. Diabetes is a disease in which the pancreas does not produce enough insulin to burn carbohydrates as an energy source for the body. Scientists believe that insulin production is determined by genes. But people with a genetic predisposition to diabetes do not always develop the disease; for example, if one identical twin has diabetes, the other will develop it about half the time. Not all environmental factors that contribute to diabetes are known yet, but there is a strong belief that obesity is one of them. An obese person needs more insulin to absorb carbohydrates than a thin person. Therefore, a person who carries the diabetes gene is more likely to develop the disease if they are overweight.

A similar situation is observed in relation to the disease schizophrenia. As we will see in Chap. 15, there is ample evidence that this mental illness has a hereditary component. If one identical twin has schizophrenia, there is a high chance that the other will show some signs of mental illness. But whether these symptoms develop into a full disease in the second twin or not depends on a number of environmental factors. Genes may create a predisposition, but the final outcome is shaped by the environment.

1. The basic unit of the nervous system is a specialized nerve cell - a neuron. From the cell body of a neuron grows a series of short branches called dendrites, as well as a thin tubular extension called an axon. Stimulation of the dendrites and cell body causes a nerve impulse to travel along the axon. Sensory neurons transmit signals from the senses to the brain and spinal cord; Motor neurons carry signals from the brain and spinal cord to the muscles and glands. A nerve is a bundle of long axons belonging to hundreds and thousands of neurons.

2. The impulse traveling along the neuron is electrochemical; it is directed from the dendrites to the end of the axon. This moving impulse, or action potential, is caused by a self-sustaining depolarization process that changes the permeability of the cell membrane to different types of ions (electrically charged atoms and molecules) drifting in and around the cell.

3. After its occurrence, the action potential travels along the axon to many thickenings at its end, which are called synaptic terminals. They secrete chemicals - mediators that are responsible for transmitting a signal from one neuron to a neighboring one. Transmitters penetrate through a narrow gap at the point of contact of two neurons (called a synaptic cleft or synapse) and bind to receptors on the cell membrane of the receiving neuron. Some mediator-receptor compounds cause depolarization of the cell membrane, and some cause polarization. If depolarization reaches a threshold level, an action potential occurs and propagates along the receiving neuron. The emergence of an action potential occurs according to the “all or nothing” law. There is a wide variety of neurotransmitter-receptor interactions that help explain a range of mental phenomena.

4. There are many different types of neurotransmitter-receptor interactions with which we can explain a range of psychological phenomena. The most important transmitters are acetylcholine, norepinephrine, dopamine, serotonin, gamma-aminobutyric acid (GABA) and glutamine.

5. The nervous system is divided into central (spinal cord and brain) and peripheral (nerves connecting the spinal cord and brain to other parts of the body). The peripheral nervous system is divided into two subsections: somatic (transmits messages to and from sensory organs, muscles and skin) and autonomic, also called autonomic (connected to internal organs and glands).

6. The human brain consists of three concentric layers: the central brainstem, the limbic system and the cerebrum. The central trunk includes: the medulla oblongata, which is responsible for breathing and postural reflexes; the cerebellum, related to motor coordination; thalamus - switching station for incoming sensory information; and the hypothalamus, which plays an important role in emotions and maintaining homeostasis. The reticular formation, passing through some of the above structures, controls states of wakefulness and arousal in the body.

7. The limbic system controls some types of instinctive activity (feeding, attack, avoidance of danger, mating), regulated by the hypothalamus; it also plays an important role in emotions and memory.

8. The cerebrum consists of two cerebral hemispheres. The convoluted surface of the hemispheres - the cerebral cortex plays a decisive role in recognition, decision-making, learning and thinking, i.e. in higher mental functions. Some areas of the cortex are specific centers for receiving sensory signals or specific centers for controlling movements. The rest of the cerebral cortex consists of association areas.

9. A number of techniques have been developed to produce detailed images of the human brain without causing unnecessary stress or damage to the patient. These techniques include computed axial tomography (abbreviated CAT or simply CT), magnetic resonance imaging (MRI), and positron emission tomography (PET).

10. If you cut the corpus callosum (a thick bundle of nerve fibers connecting the two hemispheres of the brain), significant changes will occur in the functioning of the hemispheres. The left hemisphere specializes in language and mathematics skills. The right hemisphere understands some language, but is not capable of verbal communication; he has a highly developed sense of space and structure.

11. The term aphasia is used to describe language impairment caused by brain lesions. Individuals with lesions in Broca's area have difficulty pronouncing words correctly and speak slowly and with effort. Individuals with Wernicke's area lesions can hear words but do not understand their meaning.

12. The autonomic nervous system consists of the sympathetic and parasympathetic divisions. Its role is especially important in emotional reactions, since its fibers mediate the functioning of smooth muscles and glands. The sympathetic division is active when excited, and the parasympathetic division is active when at rest.

13. Endocrine glands release hormones into the bloodstream that influence emotional behavior and motivation. They complement the nervous system in integrating behavior and their work is closely related to the activity of the hypothalamus and the autonomic nervous system.

14. A person’s hereditary potential is transmitted by chromosomes and genes and affects his psyche and physical characteristics. Genes are fragments of a DNA molecule that store genetic information. Some genes are dominant, some are recessive, and some are sex-linked.

15. Selective breeding (crossing animals based on the presence of a certain trait, weakly or strongly expressed) is one of the methods for studying the influence of heredity. Another method of analyzing the separate influences of heredity and environment is the twin study, which compares the characteristics of identical twins (who share the same heredity) and related twins (genetically similar siblings). Behavior is determined by the interaction of heredity with the environment: genes set the boundaries of a person’s potential, but what happens next with this potential depends on the environment.

Key terms

Neurotransmitter

Action potential

central nervous system

Peripheral nervous system

Somatic (nervous) system

Autonomic (nervous) system

Posterior part of the brain

Middle part of the brain

Anterior part of the brain

Central trunk

Homeostasis

Limbic system

Big brain

Behavioral genetics

Chromosome

Questions to Consider

1. Only about one tenth of brain cells are neurons (the rest are glial cells). Does this mean that we only use one tenth of our brain in the process of thinking? Probably not. What are the other possible options?

2. Local anesthesia, such as used in dental treatment, works by blocking the sodium gates in the neurons in the area of ​​the injection. Naturally, dentists and surgeons tend to give injections to the part of the body closest to the source of pain. What effect do you think a drug like this might have when injected into the brain? Will it block only pain and tactile sensations, and nothing else, or will it act in a different way?

3. Why is the brain symmetrical (meaning the external similarity of the left and right hemispheres)? Your brain has a left and right motor cortex, a left and right hippocampus, a left and right cerebellum, and so on. In each case, the left side is a mirror image of the right side (just as the left eye is a mirror image of the right eye, and the left ear is a mirror image of the right ear, etc.). Can you name the reason for this symmetrical structure of the brain?

4. In split-brain patients whose corpus callosum has been cut, the left and right sides of the brain appear to function independently after surgery. For example, a word presented to one party may be read and elicit a response without the other party knowing what the word was. Does such a patient have double minds, each capable of knowing different things? Or does such a patient also have only one mind?

5. Almost every year, the discovery of a new “alcoholism gene” or a gene responsible for drug addiction, schizophrenia, sexual orientation, impulsivity or other complex psychological trait is reported. However, upon further research, it turns out that this gene is associated with the corresponding trait only in some individuals, and not in all. It is also common for a gene to be associated with behavioral traits other than the one with which it was originally associated. Can you think of any reason why genes might influence psychological traits in this way? In other words, why is there no strict one-to-one correspondence between the presence of a gene and the severity of a particular psychological trait?

Topic 4. Behavioral genetics

Plan:

1. Definition

2. Adoption case studies

3. Twin method

Question No. 1

Behavior genetics- an approach that evaluates patterns of heredity that manifest themselves at the behavioral level - usually using psychological tests, parental self-reports, and observations of children's behavior.

Modern behavioral genetics supports the view, shared by many scientists, that complex traits are determined by the interaction of heredity and environment. For the most part, the assumption that it is genetic predispositions that are inherited, which are manifested (or not manifested) in behavior depending on environmental influences, is also shared. For example, you may inherit a predisposition to depression, but whether you actually suffer seriously from it depends on many intersecting and overlapping influences. Among them may be the following factors: how your parents and other people around you behaved towards you, what living conditions you lived in, what positive and negative experiences you encountered, etc., including what you from everything They brought this out for themselves.

The primary tool of behavioral genetics is mathematical analysis, more precisely, correlation, which is understood here as consistency: the extent to which people who are biologically related exhibit similar characteristics. Dimensions of consistency allow us to estimate heritability, that is, the degree to which a trait is inherited (rather than acquired) and therefore has some putative genetic basis. Two traditional approaches to assessing matching and heritability are adoption studies and twin studies.

Question No. 2

In classic Minnesota adoption studies The researchers compared adopted children with their biological parents, with their adoptive parents, and with their adoptive parents' biological children. In addition, they compared adoptive parents with their biological children. When comparing the test scores of adopted children and non-adopted children, the results showed that adoptive families affected the children's intellectual abilities. The sample of adopted children had a higher score on the scale IQ compared to their non-adopted peers, and they achieved greater success in school. But when researchers analyzed individual differences within sample, children's test scores were closer to the scores of their biological parents than their adoptive parents, which also shows the presence of the influence of heredity.

Other evidence in support of heritability has shown that certain attitudes, vocational interests, and personality traits appear to be highly resilient to the adoptive parent environment. Such facts are especially likely when the child's genetic predispositions are incompatible with the genetic foundation of their adoptive parents: the expression of genetically determined interests and habits may simply be delayed until the child reaches maturity and is less influenced by parental restrictions and actions .

In the years since Sandra Scarr and Richard Weinberg's research, a number of scientific papers have repeatedly emphasized the existence of at least a moderate degree of inheritance from a wide variety of psychological traits and characteristics. For example, in a seminal analysis of 24 adoption studies (including twin studies) examining heritability, the authors concluded that heritability was responsible for up to 50% of individual variation in heritability, at least as measured by parental self-report measures. child's aggressiveness. They also found an increase in the genetic contribution with age and a decrease in the familial contribution, consistent with Scarr and Weinberg's observations regarding the resistance of some heritable characteristics to environmental influences.

As a final example, we offer the work of Robert Plomin and his colleagues, who have conducted, among other things, numerous studies of adoptions and twins over the past ten years. They used data from the Colorado Adoption Project to assess whether genetic traits might partly determine something as subtle as a child's adjustment to a parent's divorce. The results were consistent with most studies of the effects of parental divorce on children. Children who experienced divorce in both biological and adoptive families showed higher levels of behavioral problems and substance abuse than children whose families remained intact. However, children of divorced biological parents showed reduced scores on measures of skills and social competence, while this phenomenon was not observed in children of divorced stepparents. The authors concluded that this was likely due to passive interaction of heredity and environment. In essence, in addition to passing on genes to their children, parents also provide them with living conditions comparable to their genes. Because of this “conformity,” family breakdown can be more dramatic for children of biological families.

Question #3

Twin studies consistently confirm that identical twins demonstrate a high degree of concordance in intellectual abilities and that they are more concordant than non-identical twins. Moreover, such results are obtained not only in the United States, but also in countries such as Japan. Based on these data, and based on other work on adopted children, it appears that intelligence has a strong genetic component. In addition, studies of antisocial behavior have shown that it is also inherited. The data from many similar studies indicate with reasonable consistency that the genetic component of intelligence is about 50%, although the nature of the development of this genetic predisposition depends largely on the environment.

Studies of twins have also revealed that a number of specific personality traits are at least partially heritable, namely emotionality, activity level and sociability. , sometimes called EAC traits. Emotionality is the tendency to easily succumb to conditions such as fear or anger. Activity level is the frequency and extent of a person's activity as opposed to a tendency toward rest and quiet. Sociability is the degree to which individuals prefer to engage in activities with others as opposed to activities alone. In general, genes are thought to contribute about 40% to personality traits, or, as twin researcher Nancy Segal argues, between 20 and 50%. Twins' similarity in emotionality, usually greater than their similarity in intelligence, also appears to persist throughout life, although the relationship between their activity levels and sociability changes somewhat during late adulthood - perhaps due to the different life events they experienced when they were not together.

Although twin studies offer us significant evidence about genetic influences in the development of different temperament types and personality styles, they cannot tell us about how genes interact with environment. A calm, non-conflict child does not encounter the same environment as an impulsive, angry, assertive child. People react differently to calm and self-confident children. Therefore, the child participates in the formation of his environment, which, in turn, sets the boundaries of the feelings he expresses and shapes the ways of expressing these feelings. Thus, the child’s personality has a huge impact on the environment in which he lives.

Research has shown that identical twins are more similar to each other than fraternal twins in personality traits such as sociability, emotionality, and activity level. But to what extent can this similarity be attributed to the influence of genes and to what extent to environmental influences?

In addition, twin studies showing relatively high heritability of traits remain a matter of debate. Unless twins are adopted into different families, they share many aspects of the family environment, which may enhance apparent heritability. Moreover, the statistical procedures used to “separate” the effects of genetic factors from environmental influences are not certain. It has also been noted that identical twins share a common maternal environment, which can have profound effects on intelligence and personality. Comparisons of identical and fraternal twins at least partially eliminate this problem, but it remains relevant in cases where identical twins are compared with siblings born separately.

At the same time, it should be noted that behavioral genetics is beginning to be combined with molecular genetics in an attempt to overcome methodological problems. It is likely that this direction will receive further development, and in the process the genetics of behavior should unfold in full force.

Behavioral genetics

(behavioral genetics) - a field of knowledge that studies genetic and trace determinants in variability animal behavior and psychological characteristics of a person (in the latter case the term human behavioral genetics is sometimes used). In Russian, in relation to the study of a person, it is more appropriate to use the term, since it is understood as a set of external actions and actions of a person, and the scope of this concept does not include, for example, sensory thresholds, psychophysiological features (see), formal characteristics of cognitive processes, etc.

Brief psychological dictionary. - Rostov-on-Don: “PHOENIX”. L.A. Karpenko, A.V. Petrovsky, M. G. Yaroshevsky. 1998 .

Behavioral genetics

A branch of genetics devoted to the study of patterns of hereditary conditioning of functional manifestations of the activity of the nervous system. The main task is to describe the mechanisms of implementation of genes in behavioral traits and highlight the influence of the environment on this process. Along with other research methods, the genetic selection method is used here, thanks to which the properties of the nervous system and behavioral characteristics can be purposefully changed. Each heritable behavioral trait usually has a complex polygenic character. Animals from lower levels of the evolutionary ladder (insects, fish, birds) are characterized by low variability in innate, instinctive actions determined by genotype. With evolutionary development, the process of formation of conditioned reflexes becomes increasingly important, and the genotype determines phenotypic variability less and less. Information important for adaptation is not only acquired in one’s own experience, but can be transmitted from parents to offspring through direct contacts, due to imitative conditioned reflexes. Data obtained in the genetics of behavior are of particular importance for the study of human nervous activity in pathologies: often mental retardation and mental illnesses are hereditary and associated with genetic disorders.

Dictionary of a practical psychologist. - M.: AST, Harvest. S. Yu. Golovin. 1998.

Behavioral genetics Etymology.

Comes from the Greek. genоs - origin.

Genetics section.

Dedicated to the study of patterns of hereditary conditioning of functional manifestations of the activity of the nervous system. Its main task is to describe the mechanisms for the implementation of genes in behavioral traits and to highlight the influence of the environment on this process. Each inherited behavioral trait, as a rule, has a complex polygenic character. Animals at lower levels of the evolutionary ladder (insects, fish, birds) are characterized by low variability in innate, instinctive acts determined by genotype. As the process of formation of conditioned reflexes acquires increasing importance in evolutionary development, the genotype determines phenotypic variability less and less. Information important for adaptation can not only be acquired through personal experience, but also transmitted from parents to offspring on the basis of direct contacts, through imitative conditioned reflexes. Data obtained in behavioral genetics are of particular importance for the study of human nervous activity in pathology: often mental retardation and mental illnesses are hereditary and associated with genetic metabolic disorders, changes in the number and structure of chromosomes.

Psychological Dictionary. THEM. Kondakov. 2000.

BEHAVIOR GENETICS

(English) behavioral genetics) - a branch of genetics that studies the patterns of hereditary determination of the structural and functional characteristics of n. With. G. p. allows us to understand the nature of the hereditary transmission of behavioral characteristics; reveal unfolding in ontogenesis chain of processes leading from genes to traits; isolate the influence of the environment on the formation behavior within the limits of potential given genotype.

Using genetic selection method properties n.With. and behavioral characteristics m.b. directionally changed. The inheritance of differences in behavioral traits is, as a rule, complex polygenic in nature.

It has been experimentally shown that the species stereotype of animal behavior has a very strict hereditary conditionality. Low variability of innate, instinctive acts is especially characteristic of animals standing at lower levels of the evolutionary ladder - insects, fish, birds, however, even in insects the behavior can be modified by production temporary connections. Moreover, behavior is not a simple result of evolutionary changes; it plays an active role in evolution, since through behavioral adaptations the effect of selection is manifested in the animal population and the regulation of its structure and numbers is ensured. Hereditary information from parents to descendants can be transmitted on the basis of direct contacts, due to the development of imitative conditioned reflexes and other ways of perceiving and transforming information (the so-called signal heredity).

Of particular importance for genetic research is the study of human nervous activity—in normal and pathological conditions. Often and mental illnesses have a hereditary etiology associated with genetic metabolic disorders, changes in the number and structure of chromosomes, etc. disorders of the genetic apparatus. Cm. . (I.V. Ravich-Scherbo.)

Large psychological dictionary. - M.: Prime-EVROZNAK. Ed. B.G. Meshcheryakova, acad. V.P. Zinchenko. 2003 .

Behavioral genetics

Field of study concerned with the genetic basis of behavior. The main thesis of this approach is that genetic differences largely explain the differences between people and their responses to the environment.

Psychology. AND I. Dictionary reference / Transl. from English K. S. Tkachenko. - M.: FAIR PRESS. Mike Cordwell. 2000.

See what “behavior genetics” is in other dictionaries:

Genetics of Behavior- a doctrine developed by J. Piaget, at the center of which is the study of psychological mechanisms that determine the structure and development of knowledge. It makes an attempt to combine the data obtained in the experiment... Psychological Dictionary

Behavioral genetics- a field of behavioral science based on the laws of genetics (See Genetics) and studying to what extent and in what way differences in behavior are determined by hereditary factors. Basic methods of studying G. p. on experimental ...

Behavioral genetics- a science that studies the role of hereditary factors in the formation of animal behavior. It is believed that most behavioral traits are controlled by many genes (polygenic inheritance) and environmental factors. Probably the more difficult... ... Trainer's Dictionary

Behavioral genetics- (behaviour genetics), the science of the genetic basis of behavior and psychologist, the savior of man. Arguments in favor of the determination of behavior by hereditary factors center around the dilemma: nature or nurture, i.e. Does it… … Peoples and cultures

Behavioral genetics- [Greek gengtikos related to birth, origin] a field of knowledge that studies genetic and environmental determinants in the variability of animal behavior and human psychological characteristics (in the latter case the term is sometimes used ... ... Encyclopedic Dictionary of Psychology and Pedagogy

Behavioral genetics- a branch of genetics that studies the connection and dependence of the hereditary gene program of a person (and in general of any living organism) and its behavior. Here the patterns of hereditary transmission of the properties of genes to the qualities and properties of human are revealed... ... Fundamentals of spiritual culture (teacher's encyclopedic dictionary)

- (behavior genetics). Study of the relationship between behavior and the genetic structure of an individual... Developmental psychology. Dictionary by book

Behavioral genetics- G.P. is nothing more than the application of genetic principles and laws to the study of behavioral variables. Intelligence, personality and psychology. anomalies are made up of three main factors. research areas in psychology, where G. p. Po’s methods are widely used... ... Psychological Encyclopedia

Genetics Great Soviet Encyclopedia

Genetics- I Genetics (from the Greek génesis origin) the science of the laws of heredity and variability of organisms. The most important task of G. is the development of methods for managing Heredity and hereditary Variability in order to obtain the forms that a person needs... ... Great Soviet Encyclopedia

Behavioral genetics is a biological discipline that studies the inheritance of innate forms of behavior. The subject of behavioral genetics is not so much evolutionary aspects as variations in inherited behavior within specific species and the actual phenomenon of inheritance of behavior. The main goal of behavioral genetics is to elucidate the role of genetic factors in determining behavioral characteristics. A number of tasks:

• · determination of the relative role and interaction of genetic and environmental influences in the formation of behavior in ontogenesis;
• · study of the heritability of stereotypical forms of adaptive behavior;
• · study of the mechanism of action of genes that determine the development of the nervous system;
• · study of the mechanisms of implementation of the action of mutant genes affecting the function of the central nervous system;
• · study of genetic and population mechanisms of behavior formation and its changes in the process of microevolution.

An important problem in behavioral genetics has become the elucidation of the relative contribution of heredity and environmental influences in the formation of a behavioral phenotype. Geneticists agreed that any form of behavior is a genetically determined norm of reaction to the environment. But it was important for them to determine the relative contributions of genetic and environmental factors to the development of various forms of behavior.

History of behavioral genetics

The existence of a scientific discipline is usually counted from the appearance of the first research in this field. The inheritance of the complex of anger, fearfulness and savagery in rats, described in 1913 by the American researcher Dzoi Yerkes, is the first experimental work on the genetics of behavior.

The beginning of self-determination of behavior genetics is usually considered to be the year of publication of the first general monograph by American scientists J. Fuller and W. Thompson, “Behavior Genetics” (Fuller, Thompson, 1960). The book was a huge success among biologists of various specialties. Another work important for the development of this direction was the monograph by J. Scott and J. Fuller on the genetics of dog behavior.

The work of employees of a special genetic laboratory in the USA played a significant role in the formation of a genetic approach to behavior analysis. This institution is a world-famous center founded in 1929 by geneticist K. Little.

In our country, the first genetic study of behavioral traits was the work of M.P., performed in the 20s. Sadovnikova-Koltsova. In it, an attempt was made to select rats for running speed in an experimental setup. In the last years of I.P.’s life. Pavlov in Koltushi, a laboratory of genetics of higher nervous activity was organized, the task of which was to study the genetic basis of the individual characteristics of conditioned reflex activity (i.e. types of HNI) of dogs. In this laboratory at the end of the 30s L.V. Krushinsky began research into the genetics of dog behavior. In their content and methodology, they are practically unparalleled to this day.

In our country, genetic studies of animal behavior were carried out in several laboratories, each of which developed its own original direction. Laboratories created in the 30-40s by M.E. Lobashev (1907-1971) and V.K. Fedorov (1914-1972) in Koltushi (Pavlov Institute of Physiology, USSR Academy of Sciences), studied the problems of genetic determination of the properties of the nervous system, as well as (together with the Department of Genetics of Leningrad State University) issues of comparative genetics of behavior.