Method of study of genetics based on learning. Methods of genetic studies

Municipal General Education

secondary school №37

Methods of human genetic research

Smolensk 2010.

Introduction

1.Genetic as science

1.1 The main stages of the development of genetics

1.2 Basic Genetic Tasks

1.3 Basic sections of genetics

1.4 Effect of Genetics on Other Biology Biology

2. Humangenetic man (anthropogenetics)

3. Meetings of study of heredity

3.1 Genealogical method

3.2 Twins Method

3.3 cytogenetic (karyotypic) methods

3.4 Biochemical Methods

3.5 Population Methods

Conclusion

Literature

application

Introduction

If the age of XIX rightfully entered the history of the world civilization as a century of physics, then the rapidly completed century of the XX-MU, in which we were lucky to live, in all likelihood, the place of the century of biology was deed, and maybe the century of genetics.

Indeed, for incomplete 100 years after the secondary discovery of the laws of Mendel Genetics, the triumphal path from the Naturofilosian understanding of the laws of heredity and variability through the experimental accumulation of the facts of formal genetics to the molecular biological understanding of the essence of the gene, its structure and functions was held. From theoretical constructions about the gene as an abstract unit of heredity to understand its material nature as a fragment of a DNA molecule encoding the amino acid structure of the protein, prior to cloning of individual genes, creating detailed genetic maps of human, animals, identification of genes whose mutations are conjugate in hereditary ailments, developing biotechnology methods and Genetic engineering, allowing you to essential to obtain organisms with given hereditary features, as well as to conduct a directional correction of mutant human genes, i.e. Genotherapy of hereditary diseases. Molecular genetics significantly deepened our ideas about the essence of life, the evolution of wildlife, structural and functional mechanisms for the regulation of individual development. Thanks to its successes, the decision of the global problems of humanity related to the protection of his gene pool began.

The middle and the second half of the twentieth century was marked by a significant reduction in frequency and even the complete elimination of a number of infectious diseases, a decrease in infant mortality, an increase in the average life expectancy. In developed countries of the world, the health center of health services was moved to the fight against the chronic pathology of a person, diseases of the cardiovascular system, oncological diseases.

Goals and objectives of my abstract:

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

· Give an accurate definition of the term "human genetics" and consider the essence of this type of genetics;

· Consider the methods of studying human heredity.

1. Genetics as science

1 The main stages of the development of genetics

The origins of genetics, like any science, should be sought in practice. Genetics arose due to dilution of pets and cultivating plants, as well as with the development of medicine. Since man began to use crossing animals and plants, he faced the fact that the properties and signs of the offspring depend on the properties of the elected to cross the parent individuals. Selecting and crossing the best descendants, a person from generation to generation created related groups - lines, and then rocks and varieties with characteristic hereditary properties.

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

The development of the science of heredity and variability was particularly strongly promoted by the doctrine of Ch. Darwin on the origin of species, which included the historical method of studying the evolution of organisms into the biology. Darwin himself put a lot of effort to study heredity and variability. He collected a huge number of facts, made them on their basis a number of correct conclusions, but he failed to establish the patterns of heredity.

His contemporaries, the so-called hybridizers, crossing various forms and searched the degree of similarity and differences between parents and descendants, were also unable to establish common laws of inheritance.

Another condition that contributed to the formation of genetics as science was achieved in the study of the structure and behavior of somatic and sex cells. Back in the 70s of the last century, a number of cytologists researchers (cleaning in 1972, a Strasburger in 1875) an indirect division of a somatic cell called by Kariokinosis (Shleyoker in 1878) or Mitoz (Flemming in 1882) was opened . The permanent elements of the nucleus of the cell in 1888 at the proposal of Valdera received the name "chromosome". In the same years, Flemming broke the entire cycle of cell division into four main phases: proofased, metaphase, anal and bodia.

Simultaneously with the study of the mitosis of the somatic cell, a study was taken to study the development of genital cells and a mechanism of fertilization in animals and plants. O. Herpun in 1876. For the first time, the merger of the core of the sperm with the core of the egg cell is set. N.N. Gorozhankin in 1880 and E. Strasburger in 1884 sets the same for plants: the first - for the vote, the second - for the coated bridge.

In the same Wang Beneden (1883) and others, the cardinal fact is clarified that during the development of sex cells, in contrast to the somatic, undergo the reduction of the number chromosomes is smoothly twice, and in fertilization - the merge of the female and male nucleus - the normal number of chromosomes is restored - , permanent for each type. Thus, it was shown that for each species characterized by a certain number of chromosomes.

Thus, the listed conditions contributed to the occurrence of genetics as a separate biological discipline - discipline with its own subject and research methods.

The official birth of genetics is considered to be the spring of 1900, when three botany, independently of each other, in three different countries, at different facilities, came to the opening of some of the most important patterns of inheritance in the offspring of hybrids. G. de Fris (Holland) on the basis of working with Enoter, Makov, Durant and other plants, informed "On the Law of the splitting of hybrids"; K. Kornz (Germany) established the patterns of splitting on corn and published the article "The Law of Gregor Mendel about the behavior of the offspring in racial hybrids"; In the same year, K. Chermak (Austria) spoke in print with an article (about artificial crossing at Pisum Sativum).

Science almost does not know unexpected discoveries. The most brilliant discoveries that create stages in its development almost always have their predecessors. It so happened with the discovery of heredity laws. It turned out that three botanists who discovered the pattern of splitting in the offspring of intravidal hybrids, just "moved" the patterns of inheritance, open in 1865 by Gregor Mendel and stated in the article "Experiments on plant hybrids", published in the "Labor" of natural scientists In Brynne (Czechoslovakia).

Mendel On pea plants developed methods of genetic analysis of the inheritance of individual characteristics of the body and established two fundamentally important phenomena:

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

Separate signs of organisms during crossing do not disappear, and persist in the outstanding in the same form, in which they were among the parent organisms.

For the theory of evolution, these principles had a cardinal value. They revealed one of the most important sources of variability, namely the mechanism for preserving the adaptability of signs of the species in a number of generations. If the adaptive signs of organisms arising under the control of the selection were absorbed, disappeared when crossing, then the progress of the form would be impossible.

All subsequent development of genetics was associated with the study and expansion of these principles and their annex towards the theory of evolution and selection.

From the established principal provisions, Mendel logically follows a number of problems that step by step receive their permission as genetically developed. In 1901, de Fris formulates the theory of mutations, which argues that the hereditary properties and signs of organisms change the jump-like - mutational.

In 1903, the Danish physiologist of plants V. Johannsen publishes the work "On inheritance in populations and clean lines", in which it is experimentally established that relating to one variety of externally similar plants are hereditary different - they constitute a population. The population consists of hereditly different individuals or related groups - lines. In the same study, the existence of two types of changeability of organisms are most clearly established: hereditary, determined by genes, and an unetebled, determined by a random combination of factors acting on the manifestation of signs.

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

Since 1911 T. Morgan with employees in the US Columbia University begins to publish a series of works, which formulates chromosomal theory of heredity. Experimentally, proving that the main carriers of genes are chromosomes, and that genes are located in chromosomes linearly.

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

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

In 1925 we have in the country of G.A. Naddison and G.S. Philippov on mushrooms, and in 1927, Möller in the United States on the fruit flock of Drozophile received proof of the effect of X-rays on the emergence of hereditary changes. It has been shown that the rate of mutation occurs more than 100 times. These studies have proven the variability of genes under the influence of environmental factors. The proof of the influence of ionizing radiation on the occurrence of mutations led to the creation of a new section of genetics - radiation genetics, the significance of which even more increased with the opening of atomic energy.

In 1934, T. Pinter at the giant chromosomes of the salivary glands of docks proved that the interruption of the morphological structure of chromosomes, expressed in the form of various discs, corresponds to the arrangement of genes in chromosomes established earlier purely genetic methods. This discovery began to start the study of the structure and functioning of the gene in the cell.

In the period from the 40s and at the present time, a number of discoveries were made (mainly on microorganisms) of completely new genetic phenomena, discontinued the possibility of analyzing the gene structure at the molecular level. In recent years, with the introduction of new methods of studying from microbiology into the genetics, we approached the randering of how the genes control the sequence of amino acids in the protein molecule.

First of all, it should be said that it is now fully proven that heredity carriers are chromosomes, which consist of a beam of DNA molecules.

Pretty simple experiments were carried out: from the killed bacteria of one strain, possessing a special external sign, was isolated by pure DNA and moved into live bacteria of another strain, after which the proper bacteria of the latter acquired a sign of the first strain. Such numerous experiments show that the carrier of heredity is DNA.

In 1953, F. Creek (England) and J. Watston (USA) deciphered the structure of the DNA molecule. They found that each DNA molecule is composed of two polydetoxyribonucleic chains, spirally twisted around the common axis.

Currently, approaches to solving the issue of the organization of the hereditary code and its experimental decoding are found. Genetics in conjunction with biochemistry and biophysics came close to clarifying the protein synthesis process in the cell and the artificial synthesis of the protein molecule. This begins a completely new stage of development not only genetics, but also the whole biology as a whole.

The development of genetics to this day is a continuously expanding fund of research of functional, morphological and biochemical discreteness chromosomes. In this area, a lot has already been done a lot already a lot, and every day the front edge of science is approaching the goal - the generation of the genus of the gene. To date, a number of phenomena characterizing the nature of the gene are established. First, the gene in the chromosome has a property of self-reproduced (copyrofaliation); secondly, it is able to change mutation; Third, it is associated with a certain chemical structure of deoxyribonucleic acid - DNA; Fourth, it controls the synthesis of amino acids and their sequences in the protein molecule. In connection with the latest studies, a new idea of \u200b\u200bthe gene is formed as a functional system, and the gene action on the definition of signs is considered in the holistic system of genes - genotype.

The revealing prospects for the synthesis of a living matter attract enormous attention of genetics, biochemists, physicists and other specialists.

1.2 Basic Genetic Tasks

genetics Biology Heredity Genealogical

Genetic studies are pursued by the goals of the twofold genus: the knowledge of the patterns of heredity and variability and the research paths of the practical use of these patterns. It is closely related: the solution of practical problems is based on the conclusions obtained in the study of fundamental genetic problems and at the same time delivers actual data important to expand and deepen theoretical representations.

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

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

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

Third, the problem of implementing genetic information. It is studied as genetic information is embodied in specific signs of a developing body, interacting with the effects of the environment, in one way or another changing these signs, sometimes significantly.

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

Achievements of genetics are used to select the types of crossings, which are best affecting the genotypical structure (splitting) in the descendants, to select the most effective methods of selection, to regulate the development of hereditary signs, the management of the mutation process, aimed changed by the genome of the body using genetic engineering and site-specific mutagenesis . Knowing how different methods of selection affect the genotypical structure of the original population (breed, variety), allows you to use those selection techniques that will change this structure to the desired side. Understanding the ways of implementing genetic information during ontogenesis and the influence of these processes of the environment, help choose the conditions that contribute to the most complete manifestation of the valuable features and the "suppression" of unwanted. It is important for increasing the productivity of pets, cultivated plants and industrial microorganisms, as well as for medicine, as it allows you to prevent the manifestation of a number of hereditary human diseases.

The study of physical and chemical mutagens and the mechanism of their action makes it possible to artificially receive a set of hereditaryly modified forms, which contributes to the creation of improved strains of useful microorganisms and varieties of cultivated plants. The knowledge of the patterns of the mutational process is necessary for the development of measures to protect the genome of man and animals from damage to physical (ch. Radiation) and chemical mutagen.

The success of any genetic studies is determined not only by the knowledge of the general laws of heredity and variability, but also the knowledge of the private genetics of the organisms with which work is underway. Although the main laws of genetics are universal, they have in different organisms and features caused by differences, for example, in the biology of reproduction and structure of the genetic apparatus. In addition, for practical purposes it is necessary to know which genes are involved in determining the signs of this body. Therefore, the study of the genetics of specific characteristics of the body is a mandatory element of applied research.

3 Basic sections of genetics

Modern genetics is represented by a variety of sections representing both theoretical and practical interest. Among the sections of general, or "classical", genetics are mainly: genetic analysis, the foundations of chromosomal theory of heredity, cytogenetics, cytoplasmic (extra-nuclear) heredity, mutation, modifications. Molecular genetics, ontogenesis genetics (phenogenetics), population genetics (genetic structure of populations, role of genetic factors in microevolution), evolutionary genetics (role of genetic factors in speciation and macroevolution), genetic engineering, genetics of somatic cells, immunogenetics, private genetics - genetics Bacteria, virus genetics, animal genetics, plants genetics, human genetics, medical genetics and MN. Dr. The newest sector of genetics - genomics - studies the processes of the formation and evolution of genomes.

4 Effect of Genetics on Other Biology Biology

Genetics occupies a central place in modern biology, studying the phenomena of heredity and variability, to a greater degree determining all the main properties of living beings. The universality of genetic material and genetic code underlies the unity of the whole living, and the diversity of life forms is the result of its implementation in the course of the individual and historical development of living beings. Genetics achievements include an important part of almost all modern biological disciplines. The synthetic theory of evolution represents a close combination of darwinism and genetics. The same can be said about the modern biochemistry, the main provisions of which are controlled by the synthesis of the main components of living matter - proteins and nucleic acids are based on the achievements of molecular genetics. Cytology The main attention pays for the structure, reproduction and functioning of chromosomes, plastids and mitochondria, i.e. items in which genetic information was recorded. The systematics of animals, plants and microorganisms is becoming more widely by comparing genes encoding enzymes and other proteins, as well as direct comparison of nucleotide chromosome sequences to establish the degree of kinship of taxa and determine their phyloge. Different physiological processes of plants and animals are investigated on genetic models; In particular, in the studies of the physiology of the brain and the nervous system, they use special genetic methods, drosophila lines and laboratory mammals. Modern immunology is entirely built on genetic data on the mechanism of antibody synthesis. Achievements of genetics, to some extent, often very significant, are part of an integral part in virology, microbiology, embryology. With full right we can say that modern genetics occupies a central place among biological disciplines.

2. Human genetics (anthropogenetics)

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

Genetic diseases and hereditary diseases. The importance of medical and genetic advice and prenatal diagnostics. The possibilities of genetic correction of diseases.

The human genetics is a special section of genetics, which studies the characteristics of the inheritance of signs in humans, hereditary diseases (medical genetics), the genetic structure of human populations. The human genetics is theoretical basis of modern medicine and modern health care.

Currently, it is firmly established that in the living world the laws of genetics are universal in nature, they are valid for a person.

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

social signs are characterized for a person who are not found in other organisms, for example, temperament, complex communication systems based on speech, as well as mathematical, visual, musical and other abilities;

thanks to public support, it is possible to survive and the existence of people with obvious deviations from the norm (in the wild, such organisms are unsuitable).

The human genetics studies the features of inheritance of signs in humans, hereditary diseases (medical genetics), the genetic structure of human populations. The human genetics is theoretical basis of modern medicine and modern health care. Several thousand actually genetic diseases are known, which are almost 100% dependent on individual genotype. The most terrible of these include: acidic fibrosis of the pancreas, phenylketonuria, galactosemia, various forms of crealth, hemoglobinopathy, as well as Down Syndromes, Turner, Kleinfelter. In addition, there are diseases that depend on the genotype, and on the environment: ischemic disease, diabetes mellitus, rheumatoid diseases, ulcerative diseases of the stomach and duodenum, many oncological diseases, schizophrenia and other psyche diseases.

The tasks of medical genetics are concluded in the timely identification of carriers of these diseases among parents, identifying patients of children and developing recommendations for their treatment. Genetic and medical advice and prenatal diagnosis are played in the prevention of genetically determined diseases (that is, identification of diseases in the early stages of the body's development).

There are special sections of human applied genetics (ecological genetics, pharmacogenesis, genetic toxicology) studying genetic bases of health. When developing drugs, when studying the body's reaction to the impact of adverse factors, it is necessary to take into account both the individual characteristics of people and the features of human populations.

We give examples of inheritance of some morphophysiological signs.

Dominant and recessive signs in humans

(Some features are indicated by controlling their genes) (Table number 1cm.pr.)

Incomplete dominance (indicated genes controlling signs) (Table number 2cm.pr.)

Inheritance of hair color (controlled by four genes, polymerically inherited) (Table number 3.Sm.PR.)

3. Methods for studying human heredity

The pedigree is a scheme that reflects the relationship between family members. Analyzing the pedigrees are studying any normal or (more often) pathological sign in generations of people in related links.

3.1 Genealogical Methods

Genealogical methods are used to determine the hereditary or non-deepeble character, dominance or recession, mapping chromosomes, clutch with floor, to study the mutational process. As a rule, the genealogical method is the basis for conclusions in medical and genetic consulting.

In the preparation of pedigrees apply standard designations. Person (individual), from which the study begins, is called proved (if the pedigree is drawn up in such a way that it is descended from the sample to his offspring, it is called the genealogical tree). The descendant of the marriage couple is called sibling, siblings, siblings, cousins \u200b\u200b- cousins, etc. Descendants who have a common mother (but different fathers) are called uni-utilous, and descendants that have a common father (but different mothers) - only one; If there are children from different marriages in the family, and they have no common ancestors (for example, a child from the first marriage of the mother and a child from the first marriage of his father), they are called consolidated.

Each member of the pedigree has its own cipher consisting of Roman numbers and Arab, respectively, the generation number and the individual number in the numbering of generations consistently from left to right. The pedigree should be a legend, that is, the explanation for the adopted notation. In closely related marriages, the likelihood of the detection of the spouses of the same adverse allele or chromosomal aberration is high.

We give the values \u200b\u200bfor some pairs of relatives during monogamy:

To [parents-descendants] \u003d K [Sibs] \u003d 1/2;

To [grandfather grandson] \u003d K [Uncle-nephew] \u003d 1/4;

To [cousins] \u003d K [great-grandmother] \u003d 1/8;

To [secondary sibs] \u003d 1/3;

To [four sibs] \u003d 1/128. Usually so far relatives in the composition of the same family are not considered.

Based on the genealogical analysis, a conclusion on the hereditary conditionality of the feature is given. For example, the inheritance of hemophilia was traced in detail and among the descendants of the British Queen Victoria. Genealogical analysis made it possible to establish that hemophilia A is a recessive disease, adhesive with the floor.

2 twin method

Gemini are two or more child, conceived and born with one mother almost simultaneously. The term "twins" is used in relation to man and the mammals, in which one child is born (cubs). Distinguish single-rigany and multi-seaman twins.

One-way (monosigital, identical) twins arise in the earliest stages of the zygota crushing, when two or four blastomer retain the ability to develop into a full-fledged organism. Since the zygota is divided by mitosis, genotypes of single-square twins, at least initially, completely identical. Single twins are always one sex, during the period of intrauterine development, they have one placenta.

Divisiony (dizigot, unidentic) twins occur differently - with fertilization of two or several simultaneously matched eggs. Thus, they have about 50% of general genes. In other words, they are similar to conventional brothers and sisters in their genetic constitution and can be both same-sex and in general solutions.

Thus, the similarities between single-hour twins is determined by the same genotypes, and the same conditions of intrauterine development. The similarity between the diverse twins is determined only by the same conditions of intrauterine development.

The birth rate of twins in relative figures is small and amounts to about 1%, of which 1/3 falls on monosigital twins. However, in terms of the total population of the Earth, over 30 million diverse and 15 million single-time twins live in the world.

For research on the twins it is very important to establish the accuracy of the zeality. The most accurate zigidity is set using reciprocal transplantation of small areas of the skin. Diappy twins have transplants always rejected, while monosic twins have transplanted skin pieces successfully survive. Also successfully, transplanted kidneys transplanted from one of the monosigitious twins are functioning.

When comparing one-way and variant twins, brought up in the same environment, it is possible to conclude about the role of genes in the development of signs. Conditions for post-utility development for each of the twins may be different. For example, monosic twins were separated a few days after birth and brought up in different conditions. Comparison of them in 20 years in many external signs (growth, scope, the number of grooves on fingerprints, etc.) revealed only minor differences. At the same time, the medium has an impact on a number of normal and pathological signs.

The twin method allows to make informed conclusions about the inherencebility of signs: the role of inheritance, environment and random factors in determining certain signs of a person,

Inheritability is the contribution of genetic factors into the formation of a feature, expressed in the shares of a unit or percentage.

To calculate the inheritance of signs, they compare the degree of similarity or differences in a number of signs from the twins of different types.

Consider some examples illustrating similarities (concordancy) and the difference (discordance) of many signs (Table .№4.Sm.PR.)

The high degree of similarity of single-time twins on such severe diseases such as schizophrenia, epilepsy, diabetes is drawn attention.

In addition to morphological signs, as well as voice timbre, gait, facial expressions, gestures, etc. study the antigenic structure of blood cells, serum proteins, the ability to feel the taste of some substances.

Of particular interest is the inheritance of socially significant signs: aggressiveness, altruism, creative, research, organizational abilities. It is believed that socially significant features are about 80% due to the genotype.

3 cytogenetic (karyotypic) methods

The cytogenetic methods are used primarily when studying the karyotypes of individual individuals. Man's karyotype is pretty well studied. Differential coloring allows you to accurately identify all chromosomes. The total number of chromosomes in the haploid set is 23. Of these, 22 chromosome are the same in men, and in women; They are called outosomes. In the diploid set (2n \u003d 46), each autosome is represented by two homologists. Twenty-third chromosome is a sex chromosome, it can be represented by either x or y-chromosome. Sex chromosomes in women are represented by two X chromosomes, and in men with a single X chromosome and one y-chromosome.

The change in the karyotype is usually associated with the development of genetic diseases.

Thanks to the cultivation of human cells in vitro, you can quickly get a fairly large material for the preparation of drugs. For karyotyping, a short-term culture of peripheral blood leukocytes is usually used.

Citogenetic methods are used to describe interphase cells. For example, according to the presence or absence of sex chromatin (Barra Taurus, which is inactivated X-chromosomes, you can not only determine the floor of individuals, but also identify some genetic diseases associated with a change in the number of X-chromosomes.

Mapping a man chromosome.

Methods of biotechnology are widely used for mapping human genes. In particular, cell engineering methods allow us to combine different cell types. The fusion of cells belonging to different biological species is called somatic hybridization. The essence of somatic hybridization is to obtain synthetic crops by fusion of protoplasts of various types of organisms. For fusion cells, various physicochemical and biological methods use. After the fusion of protoplasts, multi-core heterocarotic cells are formed. In the future, during the merger of nuclei, sekryotic cells are formed containing chromosomal sets of different organisms in nuclei. When dividing such cells in vitro, hybrid cell cultures are formed. Currently obtained and cultivated cell hybrids "Man × mouse "," man × rat "and many others.

In the hybrid cells obtained from different strains of different species, one of the parent genomes gradually loses chromosomes. These processes occur intensively, for example, in cell hybrids between the mouse and man. If you follow a biochemical marker (for example, a specific human enzyme) and at the same time conduct cytogenetic control, then, in the end, you can associate the disappearance of chromosome simultaneously with the biochemical sign. This means that the gene encoding this feature is localized in this chromosome.

Additional information on the localization of genes can be obtained in the analysis of chromosomal mutations (deletions).

4 biochemical methods

All variety of biochemical methods is divided into two groups:

a) Methods based on identifying certain biochemical products caused by the action of different alleles. It is easiest to identify alleles to change the activity of enzymes or by changing any biochemical feature.

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

The use of biochemical methods allows you to identify heterozygous carriers of diseases. For example, the heterozygous carriers of the phenylketonurium gene changes the level of phenylalanine in the blood.

Methods of Mutagesis Genetica

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

Gene mutations. About 1% of newborns are ill because of gene mutations, of which part of the newly arising. The pace of mutating various genes in the human genotype of unequal. It is known for genes that mutate with a frequency of 10-4 on Games for generation. However, most other genes are mutated with a frequency, hundreds of times lower (10-6). Below are examples of the most frequent gene mutations in a person (Table No. 5. CM.PR.)

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

Polyploidy in man meets very rarely. The case of triploid is known - these newborns die early. Tetraplaids are detected among aborted embryos.

At the same time, there are factors that reduce the frequency of mutations - antimutagen. AntiMutagenam includes some antioxidant vitamins (for example, vitamin E, unsaturated fatty acids), sulfur-containing amino acids, as well as various biologically active substances that increase the activity of reparation systems.

5 population methods

The main features of human populations are: the community of the territory on which this group of people lives, and the possibility of free marriage. Insolation factors, i.e., restrictions on the selection of spouses, a person may have not only geographical, but also religious and social barriers.

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

There are various forms of natural selection in human populations. The selection acts both in the intrauterine state and in subsequent periods of ontogenesis. The most pronounced stabilizing selection directed against adverse mutations (for example, chromosomal rearrangements). A classic example of selection in favor of heterozygotes is the distribution of sickle cell anemia.

Population methods allow you to assess the frequencies of the same alleles in different populations. In addition, population methods allow you to study the mutation process in humans. By the nature of the radio sensitivity, the human population is genetically heterogeneous. In some people with genetically determined defects for DNA repair, chromosomes are increased by 5 ... 10 times compared to most members of the population.

Conclusion

So, adequately to perceive the revolution on our eyes in biology and in medicine, to be able to take advantage of her tempting fruits and avoid dangerous for human temptations - that's what is needed today and doctors, biologists, and representatives of other specialties, and just an educated person.

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

In my abstract, I set the tasks that I needed to consider. I learned more about genetics. I learned what kind of genetics. Considered its main stages of development, tasks and objectives of modern genetics. Also, I considered one of the species of human genetics - genetics. Gave the exact definition of this term and considered the essence of this type of genetics. Also in my abstract, we considered the types of study of man's heredity. Their varieties and essence of each method.

Literature

·Encyclopedia. Human. Volume 18. Part One. Volodin V.A.- M.: Avolta +, 2002;

·Biology. Common laws. Zakharov V.B., Mamontov S.G., Sivhogrov V.I. - M.: School press, 1996;

·<#"justify">application

Table No. 1 Dominant and recessive features in humans (for some signs there are controlling their genes)

DominantnyeRetsessivnyeNormalnaya pigmentation of the skin, eyes, volosAlbinizmBlizorukostNormalnoe zrenieNormalnoe zrenieNochnaya slepotaTsvetovoe zrenieDaltonizmKataraktaOtsutstvie kataraktyKosoglazieOtsutstvie kosoglaziyaTolstye gubyTonkie gubyPolidaktiliya (extra toes) Average number paltsevBrahidaktiliya (short fingers) Normal paltsevVesnushkiOtsutstvie length vesnushekNormalny sluhVrozhdennaya gluhotaKarlikovostNormalny rostNormalnoe assimilation glyukozySaharny diabetNormalnaya clotting kroviGemofiliyaKruglaya face shape (the R-) square face shape (rr) Piece on the chin (a-) The absence of a hole (AA) of the pits on the cheeks (D-) the absence of snaps (DD) thick eyebrows (B-) Thin eyebrows (BB) Eyebrows are not connected (N-) Eyebrows Connect (NN) Long Eyelashes ( L-) short eyelashes (LL) Round nose (G-) Pointed nose (GG) Round nostrils (Q-) Narrow nostrils (QQ)

Table number 2 Nefive dominance (indicated genes controlling signs)

SignaturesTeeRexuality Between Eyes - Table-Eye Eyes - Eye Eye - EBOLESHIONMEDIENTINGEIMERS MERS - MBLSHOWSHIPMALLYSHIPHIP - SkurchasawayInstrievable Browsticks - Nose Night Nose - Fabric Summary Table number 3 Inheritance of hair color (controlled by four genes, polymerically inherited)

Number of dominant allelestillers Hair 88Temn-brown68-brown5ChishTowNew4Realous3Rell-blonde2Loun Blond1Other light blondeble

Table number 4.

a) the degree of difference (discordance) for a number of neutral signs in the twins

Symptoms controlled by a small number of genesis (probability) of differences,% inheritability,% single-trigger softener Eye0,57299Form ears2,08098The highway hair3,07796Papillary lines8,06087< 1 %≈ 55 %95 %Биохимические признаки0,0от 0 до 100100 %Цвет кожи0,055Форма волос0,021Форма бровей0,049Форма носа0,066Форма губ0,035

b) the degree of similarity (concortanity) for a number of diseases in the twins

Symptoms controlled by a large number of genes and dependent non-mental factors for the emergence of similarity,% Instruction,% single-trigger disorderly retardation973795Sofractions691066Sharynx diabetes651857Epilippsy673053444% ≈ 20% ≈ 65% Crime (?) 682856%

Table number 5.

Types and names of mutation of mutations (per 1 million heights) Autosomal dominant polyquicistosis of kidney65 ... 120Neurochibromatosis65 ... 120 multiply polyposis of the colon 10 ... 50anomalia leukocyte Pelger9 ... 27 osteogenesis7 ... 13 SINMISSIMER4 ... 6Aychtiosis ( Not fitted with floor) 11Pronsive, adhesive with hairless dystrophy Duchin43 ... 105Gemophilia A37 ... 52Gemophilia B2 ... 3 ichtiosis (hooked with floor) 24

Clinical and genealogical method It was introduced at the end of the XIX century F. Galton. It is based on building pedigree and tracking in a number of generations of transferring a certain feature.

Stages of genealogy analysis:

1) collecting data on all relatives of the surveyed (history);

2) building a pedigree;

3) Analysis of pedigree and conclusions.

The method allows you to set:

1) whether this feature is hereditary;

2) the type and nature of inheritance;

3) Surgery of pedigree persons;

4) penetrant gene,

5) The likelihood of the birth of a child with this hereditary pathology.

Drop the pedigree Start from collecting information about the family of consulting or sample. Consultanta person who appeals to the doctor is called, or the first person in sight of the researcher. Proved- Patient or carrier of the studied sign. In many cases, consulting and proved are the same face. Children of one parent couple are called sibsami(brothers and sisters). Familyin a narrow sense, they call the parent pair and their children, but sometimes a wider range of blood relatives, although in the latter case it is better to apply the term rod.The complexity of the collection of anamnesis is that the problem should know well, in the possibility, most of their relatives and the state of their health.

Clinical and syndromological method allows you to identify the morphological, biochemical and functional signs of hereditary forms of pathology (for example, a deficiency of plasma factor VIII with suspected hemophilia A; karyotype 45, x0 in suspected shernesevsky Syndrome - Turner; lesions of the skeleton, sss and eyes when suspected martan Syndrome).

Twin method The study of human genetics was introduced into the medical practice of F. Galton in 1876. It allows you to determine the role of the genotype and environment in the manifestation of signs.

Distinguish mono and dialicate twins. Monosigital (single) twins They develop from one fertilized egg, have a completely identical genotype and, if they differ in phenotypically, this is due to the impact of the factors of the external environment. Dialization (Bicycle) twins After fertilizing with spermatozoa of several simultaneously matched eggs, there will be different genotypes, and their phenotypic differences are due to both the genotype and the factors of the external environment. Monosic twins have a greater degree of similarity on the signs that are determined mainly by the genotype. For example, monosigital twins are always single-salts, they have identical blood groups for different systems (ABO, RH, MN, etc.), the same eye color, the same type of dermatoglyphic indicators on the fingers and palms, etc. These phenotypic signs and are used as criteria for diagnostic diagnostics twins.

The percentage of the group of twins on the studied attribute is called concordance, and percentage differences - discordance. Since monosigital twins have the same genotype, the concordance of them is higher than that of dizigoty.

To assess the role of inheritance and environment in the development of one or another feature use holzinger's formula:

KMB% - KDB%

where H is the proportion of heredity, KMB% - the concortancy of monosigital twins, CDB% - the concortancy of dialicate twins.

Population statistical method The study of human genetics is based on the use hardy Weinberg Law. It allows you to determine the frequency of genes and genotypes in people's populations. For example, homozygotes on the HBS gene in Belarus practically do not occur, and in Western Africa countries will range from 25% in Cameroon to 40% in Tanzania. The study of the proliferation of genes among the population of various geographic zones (genomegography) makes it possible to establish the centers of origin of various ethnic groups and their migration, determine the degree of risk of the appearance of hereditary diseases in individual individuals.

Citogenetic method Based on microscopic examination of chromosomes in order to identify structural disorders in a chromosomal set (Karyotyping).The material uses tissue cultures with a large number of cells dividing cells, more often in peripheral blood lymphocytes. Chromosome at the metaphase stage is studied using special methods of staining and are idiograms (systematized karyotypes with a chromosoma location from the largest to the smallest).

Stages of the method:

1) cultivation of human cells (more often than lymphocytes) on artificial nutritional media;

2) stimulation of phytohemagglutinin mitosis (FGA);

3) adding a colchicine (destroys the filament of the separation of division) to stop mitosis at the metaphase stage;

4) the treatment of cells with a hypotonic solution, as a result of which the chromosomes are scattered and lying freely;

5) chromosomes;

6) studying under the microscope and photographing;

7) cutting with individual chromosomes and the construction of an idiogram.

The method allows you to identify genomic (for example, dauna disease) and chromosomal (for example, a cat shout syndrome) mutations. Chromosomal aberrations denote chromosome number, short or long shoulder and excess (+) or lack of (-) genetic material. For example, a feline cry syndrome indicates: 5p.

Biochemical methods Based on the study of the activity of enzyme systems (or by the activity of the enzyme itself, or by the amount of finite reaction products catalyzed by the enzyme). They allow you to identify gene mutations - the causes of metabolic diseases (for example, phenylketonuria, sickle cell anemia). With the help of biochemical load tests, heterozygous carriers of pathological genes can be detected, for example, phenylketonuria. An intravenous amount of phenylalanine amino acid amino acid is introduced under investigation and at regular intervals of the time is determined by its blood concentration. If a person is homozygoten for a dominant gene (AA), the concentration of phenylalanine in the blood returns rather quickly to the control level (it is determined before the administration of phenylalanine), and if it is heterosigoten (AA), then the decrease in the concentration of phenylalanine is twice as slower. Similarly, tests are conducted, revealing predisposition to diabetes, hypertension, etc. diseases.

Research objects:

· Metabolites in biological fluids and cells (for example, phenylalanine in phenylpyrograde oligophrenia; ketone bodies (CT) with diabetes mellitus);

· Anomalous proteins (for example, ny with hemoglobinopathy);

· Defective enzymes (for example, cholinesterase, glutathioneer peroxidase, catalase).

Stages of research:

· The first is the use of screening programs of diagnosis (for example, thin-layer chromatography, electrophoresis, microbiological methods);

· The second is the use of confirmation methods (for example, fluorometric, spectrophotometric, quantitative determination of metabolites, testing the activity of the enzyme).

Molecular diagnostics. These methods allow you to analyze DNA fragments, find and insulate individual genes and gene segments and set a sequence of nucleotides in them. For wide use in practical health care methods of recombinant DNA, it is necessary to create libraries of radioactive probes of all DNA sequences of the human genome, which is now successfully executed.

1. DNA cloning method Allows you to isolate individual genes or parts them, transcribe (create copies of them) and broadcast insulated genes. This became possible thanks to the discovery of restrictase enzymes.

2. Hybridization of nucleic acids. In this method, the method of linear segments of two-stranded DNA are subjected to heat treatment and get single-stranded fragments (denaturing). Denaturized DNA is incubated under such conditions (T \u003d 37 ° C) when hybridization occurs, i.e. Mutual recognition of two complementary threads by pairing nitrogenous bases. Often, one radioactive thread of DNA is used to identify the procedure for nucleotides as a "probe". You can identify both completely and partially homologous sequences. The specificity of hybridization of nucleic acids makes it possible to detect the only gene among tens of thousands. Various modifications of this method allow in the clinic to analyze very small amounts of DNA taken from the patient.

Blot hybridization.To identify those who are interested in (including mutant), the DNA genes are restricted. The resulting DNA fragments are divided into molecular weight, denatured and transferred to the carrier (nylon or other membrane). Fixed on a carrier in the form of a DNA stain hybridize with a labeled radioactive isotope of DNA or RNA probe. As a result, the position of the anomalous DNA fragment is determined.

3. Polymerase chain reaction (PCR)it is used to study regions of the alleged mutations and other features of the DNA structure. For research, any biological material containing DNA can be used (for example, a piece of fabric, a drop or blood stain, flushing the oral cavity, hair root bulb). At the first stage, the studied DNA is subjected to annealing: split into two threads when heated to 95-98 ° C. Then one of the threads hybridize and stimulate the synthesis of the sequence, complementary DNA studied (using thermophilic DNA polymerase). In the first CCR cycle, hybridization is performed with the studied DNA fragment, and in the following - with newly synthesized. With each reaction cycle, the number of synthesized copies of the DNA section increases twice. Cycles are repeated before accumulating the desired amount of DNA. I developed this technique and suggested Cary Mullis.

Methods of genetics of somatic cells make it possible to learn many questions of human genetics in the experiment. For cultivation, cells of connective tissue (fibroblasts) and blood lymphocytes are more often used. On artificial nutritional environments clone. Receive descendants of one cell. All of them will have the same genotype (like monosic twins) and, therefore, at the cellular level, it is possible to study the role of the genotype and environment in the manifestation of signs.

Can be carried out selection Cells - cell selection with predetermined properties. For this, selective nutrient media use. For example, if you do not add to the nutrient medium not lactose, and other sugars, then from a large number of cells there are several, which can exist without lactose, and in the future you can get a clone of such cells.

The greatest interest for human genetics represents the method hybridization somatic cells. In 1960, the French scientist J. Barsky, growing in the culture of the cell two lines of mice, found that some of them were intermediate between the initial parent cells in their morphological and biochemical properties. These were hybrid cells. Such a spontaneous merger of somatic cells in the tissue culture is quite rare. In the future, it was found that when the cells of the RNA-containing virus of paragrippa sendai, inactivated by ultraviolet, inactivated during ultraviolet irradiation, is significantly increased, and in the mixed culture of different types of cells are formed. heterocarions - Blots containing two cores of different cells in one cytoplasm. Some of these cells can multiply by mitosis. After mitosis of the two-core heterocarion, two single-core cells are formed, each of which is sinkarion - a real hybrid cell containing chromosome of both source cells.

Hybridization is possible not only between the cells of organisms of different types, but also types: a man-mouse, a commander, and others. Sinkarions usually manage to obtain cells of different types related to one class. In such Sinkarions, the genomes of two species occur. For example, hybrid cells of a person and mice have 43 pairs of chromosomes: 23 - from man and 20 - from the mouse. In the future, there is a gradual removal of chromosoma of that organism, the cells of which have a slower pace of reproduction. Hybrid cells man-mouse removes human chromosomes. In hybrid cells, chromosomes both human and mice are functioning, whose genes are determined by the synthesis of the corresponding proteins. Morphologically you can distinguish each of the chromosomes (differential staining). If there is no chromosome in the hybrid cell and the synthesis of some proteins does not occur, it can be assumed that the genes determining the synthesis of these proteins are localized in this chromosome. Thus, the method allows you to install the clutch groups in humans, and using shortages and translocations - to find out the sequence of gene location, i.e. build genetic maps chromosomes man.

Biological modeling certain hereditary human anomalies can be carried out on mutant animal lines that have similar violations. For example, dogs occur in hemophilia due to recessive adhesive with the X-chromosome (with floor) genome; the misractiveness of the lip and the sky in mice is similar to similar human anomalies; Khamiakov and rats meet diabetes mellitus, ahondroplasia, muscle dystrophy, etc. Although mutant animal lines do not give an accurate picture of hereditary human diseases, even partial reproduction of their fragments in some cases allows us to study the primary deviation mechanisms from the norm. The law of homologous rows N. I. Vavilov (types and childbirth genetically close have similar rows of hereditary variability) Allows you to extrapolate experimental data on a person with certain limitations.

Math modeling - This is a method for creating and studying mathematical models. It is used to calculate the frequencies of genes in populations in various influences and environmental changes. Mathematical methods are widely used in cases where it is impossible to use experimental methods (for example, an analysis of a large number of adhesive genes in humans).

Medical geneticizes the role of heredity and variability in the emergence, development and outcomes of human pathology, develops methods for diagnosis, treatment and prevention of hereditary and non-aulties.

Medical genetics as science is based on a number of principal provisions that reveal the essence of the problem of hereditary human diseases and currently adopted as axioms:

Hereditary diseases are part of the overall hereditary variability of man. There is no sharp boundary between hereditary variability leading to a change in normal signs, and variability leading to the emergence of hereditary diseases;

In the development of hereditary signs or diseases take part hereditary constitution and external environment. At the same time, heredity plays a decisive role for the development of some signs or diseases, and an external environment is essential, but there are no such signs that depend only on heredity or only on the environment;

Hereditary burdelessness of modern humanity consists of the pathological mutations accumulated during the evolution and from newly emerging hereditary changes in the genital cells. Quantitative volume of new mutations may increase under the influence mutagenic factors:

Ionizing radiation;

Chemical substances;

Other impacts;

human habitat continues to change, which leads to the emergence of new types of hereditary pathology - eco-generic diseasesSince changing genetic human population structure:

The circle of potential marriage partners has expanded;

Wide scale reached the migration of the population;

Modern medicine has great opportunities in the diagnosis, treatment and prevention of hereditary diseases, and in the future will have even large. The patient or carrier of the pathological deposit is a full member of society and has equal rights with a healthy person. The progress of medicine and society leads to the following:

An increase in the life expectancy of patients with hereditary diseases;

Restoration of their reproductive function;

And, therefore, the growth of their number in the population.

Medical genetics helps to understand the interaction of biological and medial factors in human pathology. Based on medical and genetic knowledge, the skills of the diagnosis of hereditary diseases are purchased.

Currently there was a slender system of prevention of hereditary diseasesWhere include:

Medical and genetic consulting;

Perinatal diagnostics;

Mass diagnosis in newborn hereditary diseases of the exchange, domestic and drug therapy;

Dispensarization of patients and their family members.

The introduction of this system has reduced the birth rate of children with congenital defects and hereditary diseases by 60-70%.

Based on the achievements of genetics already implemented in practical health, such perspectives can be predicted:

Wide application preimplantation diagnostics in major medical and genetic centers;

Holding genetic testing in illness with hereditary predisposition and adoption, according to the results obtained, preventive measures;

The creation of new approaches and treatment methods (including gene therapy individual diseases);

Production new types of drugs based on gene information;

The population of secondary and older can be examined for the risk of many diseases that can be warned or facilitated by dietary or drug impact;

Checking individual sensitivity to drugs molecular genetic method Must become a standard procedure to any medication treatment.

Medico-genetic counseling

The industry of preventive medicine, the main purpose of which is to prevent the birth of children with hereditary pathology. The emergence of genetic advice as an independent institution is usually associated with the name S.S. REED (1947), however, in the 1930s, the Russian clinician genetic S.N. Davidenkov He conducted genetic consulting and formulated the main provisions on the method of counseling families with hereditary diseases of the nervous system (1934). Modern genetic consultation is designed to serve the interests of the family and society.

Purpose of genetic consultation - Establishment of the degree of genetic risk in the examined family and clarification of spouses in the affordable form of medical and genetic conclusion.

Tasks of medical and genetic counseling:

1) Pro- and retrospective (before and after birth) consulting families and patients with hereditary or congenital pathology;

2) the prenatal diagnosis of congenital and hereditary diseases;

3) assistance to doctors of various specialties in the formulation of the diagnosis of the disease, if this requires special genetic research methods;

4) an explanation in the affordable form to the patient and his family degree of risk to have sick children and help them in decision making;

5) keeping the territorial register of families and patients with hereditary and congenital pathology and their dispensary observation;

6) Propaganda of medical and genetic knowledge among the population.

In short, the task of genetic consultation is to draw up a genetic forecast in the individual of the individual with an anomaly of physical, mental or sexual development and the choice of preventive measures to prevent the birth of a patient child.

Drawing up a genetic forecast.

1. Determining the degree of genetic risk. Under the genetic risk, the likelihood of the manifestation of a certain anomaly in the patient (proband) or its relatives, which is expressed as a percentage (from 0 to 100%). The general risk of the appearance of genetically determined anomaly for Europeans populations is 3-5% (genetic cargo), therefore the risk that does not exceed 5% is regarded as low. Genetic risk up to 10% is referred to as elevated in an easy degree, up to 20% - elevated in the average degree and more than 20% are high. From a genetic point of view, you can neglect the risk that does not go beyond the limits of an increased in an easy degree, and not consider it by contraindication to further confidence, even when there is no possibility of prenatal diagnosis of the alleged anomaly. Genetic risk middle degree It is estimated as a contraindication to childbirth, i.e. As an indication for the interruption of pregnancy, if the family does not want to be at risk.

Man is an uncomfortable object for studying genetics. This is due to the biological and social characteristics of human life. Therefore, special methods of studying the human genetics are applied, which allow you to predict risks and warn deaths.

Goal

The developed methods of research of human genetics pursue an important goal - to find a way to extend the life and improving public health. Perhaps, in the future, genetics will solve the problem of aging, will learn how to adjust the genetic code, which will reduce the predisposition and the development of incurable genetic diseases.

Modern human genetics studies different aspects of life associated with genetic material and affects the following problems:

genetic foundations of the physiological and anatomical features of tissues, organs, the body as a whole;
causes of predispositions, abilities and talents in a certain field of activity;
regularities of the distribution of genes between descendants;
causes and ways of preventing genetic diseases;
genetic conditionality of memory, thinking, emotions;
mechanisms for the emergence of useful and harmful mutations.

The human genetics is closely related to medicine and anthropology. With the knowledge of the genetics of scientists-doctors find ways to combat pathologies of nervous, humoral, blood systems, oncological diseases. Reading genetic information helps to study the evolution of man.

Methods

Studies related to man are faced with several difficulties of biological and socio-ethical.
Biological problems include:

work with a large number of chromosomes;
late sexual maturity of man;
a long period of pregnancy is the impossibility of obtaining offspring in a short time;
long generation change (for 20-25 years);
low fertility - one or two descendants for one pregnancy.

Fig. 1. Man karyotype.

Social problems of studying human heredity are:

the impossibility of experimental crossing is impossible to use human life for scientific purposes;
the complexity of creating equal environmental conditions for observations - each person is unique due to social education and character traits, so the level of even two lives is almost impossible.

The main methods of study are described in the Table methods of the study of human genetics.

*Method*	*Description*	*Value*
Popular statistical	Collection and analysis of statistical data of groups of people (representatives of one population)	Forecast of distribution of diseases and inheritance in the population
Biochemical	Detects disorders of genes that are responsible for metabolism	Detection of predisposition to various metabolic diseases - diabetes, phenylketonurium, lactase deficiency
Dermatoglyphic	Study of the skin relief on the fingers (dactyloscopy), palms (palmoscopy), stop soles (ploscopy)	Used to determine the individual in the diagnosis of hereditary diseases, in forensic medicine
Twin	Studying and comparison of phenotypes and genotypes of one-way and bilayer twins in different conditions	The ability to track the influence of the external environment on the development of a certain feature or illness (schizophrenia, epilepsy)
Genealogical	Studying a pedigree person with the aim of observing the inheritance of phenotypic signs and predispositions for diseases in subsequent generations. Detection of dominant and recessive genes	Polydactilia (Sinipality), diabetes, early baldness, albinism, deafness, poliomyelitis, etc.
Cytogenetic	Analysis of the karyotype in the norm and in the presence of pathology	Study of chromosomal diseases - Down syndromes, Klinfelter, Turner-Sherchezhevsky, cat shouting syndrome