∙ mixed infertility (a combination of forms of female and male infertility). CONTRAINDICATIONS

∙ somatic and mental illnesses that are contraindications to pregnancy;

∙ congenital anomalies: repeated births of children with the same type of developmental defects; previous birth of a child with chromosomal abnormalities; dominantly inherited diseases in one of the parents with high degree penetrance;

∙ hereditary diseases: heterozygous carriage in spouses for any monogenic diseases (disorders of amino acid, carbohydrate, glycolipid, glycoprotein metabolism). Previous birth of children with diseases that are inherited and linked to sex (hemophilia, Duchenne type myopathy, etc.);

∙ hyperplastic conditions of the uterus and ovaries;

∙ defects and anomalies of the uterus;

∙ untreatable disorders of the cervical canal.

Experts advise starting the examination of a married couple with the man, since a semen analysis will immediately show the cause of male infertility, and diagnosing female infertility is a complex and lengthy matter. In order for the spermogram to be informative, it is necessary to abstain from sexual activity for 3-5 days before submitting sperm for analysis (preferably no less, but no more). It is best to donate sperm for analysis in the same room where the laboratory is located. Cooling sperm leads to distortion of most indicators of its quality.

The next stage of the examination is a compatibility test. Incompatibility can be immunological and biological. It determines the cervical factor of infertility: cervical mucus, in case of incompatibility, reduces chemotaxis or “kills” sperm. The woman is then examined to diagnose female infertility. After making a diagnosis and clarifying the causes of infertility, as a rule, they move on to the treatment process itself.

TREATMENT WITH IVF METHOD.

First, with the help of hormones, it is necessary to achieve the maturation of several eggs in the ovaries at once (superovulation). The main drugs in the first stage are gonadotropin-releasing hormone (α-HLH) agonists, human menopausal gonadotropin (HMG) drugs and human chorionic gonadotropin (hCG) drugs. They are administered according to developed treatment regimens or “protocols for stimulating superovulation.” The maturation process is monitored using ultrasound and determining the level of hormones (estradiol).

Shortly before the spontaneous process of ovulation (the release of an egg from the ovary), follicle puncture and aspiration of eggs are performed. It is very important to determine the moment when the follicles should be punctured (collected) (as close as possible to the time of natural ovulation), which

done using ultrasound and determining the concentration of hormones in the blood serum.

Transvaginal puncture is carried out under ultrasound control 36 hours after the administration of chorionic gonadotropin using special puncture needles.

Transvaginal puncture is performed in an operating room equipped with all the necessary instruments and equipment for emergency surgical care (ventilator and others). Pain relief is used depending on the woman’s condition. Collection, that is, aspiration of follicles, is carried out from both ovaries.

Receipt and preparation of spermatozoa. To prepare them for fertilization, the so-called capacitation is carried out, i.e. washing sperm from plasma elements, then using special methods to prepare a solution with viable sperm.

After approximately 5-7 hours of being in the nutrient medium, the eggs and sperm are joined (ovum insemination) in a “test tube” and placed in an incubator for 24-42 hours. The day of puncture is considered day zero of embryo culture (0D); The first day of cultivation (1D) is considered to be the day following the puncture. It is on this day that the first signs of fertilization become noticeable for most. They appear, as mentioned above, 16 - 18 hours after mixing eggs with sperm (insemination). Fertilization is reassessed 24 to 26 hours after insemination. Control of oocyte fertilization is carried out by a laboratory assistant-embryologist when viewing dishes with cultured cells under a microscope. However, their presence is not yet sufficient to resolve the issue of the possibility of transferring embryos into the uterine cavity. First you need to make sure that the embryos are splitting and developing normally. This can only be judged based on the quantity and quality of the dividing cells of the embryo and not earlier than one day after fertilization, when the first signs of fragmentation appear. They appear most clearly only on the second day of cultivation (2D). Only good quality embryos can be transferred. Embryo transfer is usually carried out on the 2nd or 3rd day of cultivation, depending on the rate of their development and the quality of the embryos.

The transfer of embryos into the uterine cavity is carried out using special catheters in minimum quantity nutrient medium(20-30 µl). It is recommended to transfer no more than 3 - 4 embryos into the uterine cavity, since when transferring a larger number of embryos, implantation of two or more embryos is possible. The transfer of embryos into the mother's uterus is usually carried out without anesthesia. Next, the woman needs to be prescribed medications that support implantation and development of embryos. Diagnosis of pregnancy is carried out from the tenth day after the transfer of artificially fertilized embryos. Women who become pregnant after using the IVF and ET method are considered to be at high risk and

must be under constant supervision of an obstetrician-gynecologist. After the embryo transfer, the woman receives a sick leave certificate with a diagnosis of “Early pregnancy, threat of miscarriage.”

The effectiveness of IVF today is on average 20-30%,

but in some centers it exceeds 50%. This is a very high percentage, especially if you remember that the probability of conception in a natural cycle in a completely healthy man and woman in one copulatory cycle does not exceed 30%. These are the medical aspects of this problem. There are also moral, ethical and religious problems associated with in vitro fertilization. In particular, many religious denominations prohibit believers from resorting to IVF, considering this method of childbirth to be sinful. In the basics of legislation Russian Federation of July 22, 1993 (section 7, article 35 “Artificial insemination and embryo implantation”) states that every adult woman has the right to artificial insemination and embryo implantation.

IVF makes it possible to carry out preimplantation diagnostics of hereditary (genetic) diseases of the future fetus before the embryo is transferred to the uterus, that is, before pregnancy occurs. You can consciously approach solving an important problem if your family has children suffering from genetic diseases. Preimplantation diagnosis of chromosomal aberrations is carried out by FISH, PCR or cytogenetics.

IVF is also widely used to solve problems in basic biology and medicine.

5.5 Cloning of organisms, organs and tissues. The problem of cloning has recently acquired an acute social resonance, since the means mass media They often present the essence of the issue incompetently.

According to the definition accepted in genetics, cloning is the exact reproduction of a living object. The main criterion for a clone is genetic identity. Cloning is widely used in plant growing, microbiological industry, and experimental embryology. There are known cases of natural cloning in humans - these are identical twins. However, currently we are talking about obtaining exact copies of an adult animal or person with especially valuable qualities.

The theory of cloning is based on the experiments of J. Gurdon, who transplanted the nuclei of cells of the integumentary epithelium into the nucleated eggs of frogs and obtained tadpoles from them. In May 1997, Ian Wilmut from Scotland published the results of cloning sheep (the famous Dolly). Clearly speculative publications have also appeared about successful attempts at human cloning.

A scientific analysis of the data presented has shown that there is no talk of effective cloning of animals and humans yet.

Firstly, the practical yield of cloning is 1-2%, secondly, the genetic identity of cloned organisms has not been proven, and thirdly, the viability and functionality of “clones” turned out to be incomparably lower than their natural analogues.

There are other reasons why, at the current level of scientific development, mass cloning of mammals and humans is not possible. There are also social and ethical problems of cloning, which are unlikely to be resolved in the near future.

On a completely different plane lies the problem of cloning organs and tissues of animals and humans for the purpose of transplantation. This is a truly promising and practically significant task that is being successfully solved. It has been proven that transplanting a clone of the patient’s own cells or pre-grown tissue (organ) is preferable to donor material: problems of immunological incompatibility disappear, the accuracy of transplant dosage increases, it is possible to create banks of cells, tissues and organs, unique opportunities for experimental research appear, ethical issues disappear problems, etc.

LITERATURE

1. Asanov A.Yu., Demikova N.S., Morozov S.A. Fundamentals of genetics and hereditary developmental disorders in children. M.: Publishing Center

"Academy". 2003. – 224 p.

2. Baranov V.S. Prenatal diagnosis of hereditary and congenital diseases in Russia. – Soros educational magazine. – 1998. - No. 10. -

3. Baranov V.S. Gene therapy is medicine of the 21st century. – Soros educational magazine. – 1999. - No. 3. - WITH. 63-68.

4. Baranov V.S., Baranova E.V., Ivashchenko T.E., Aseev M.V. Human genome and “susceptibility” genes. Introduction to predictive medicine. St. Petersburg: "Intermedica". 2000. – 271 p.

5. Barashnev Yu.I., Bakharev V.A., Novikov P.V. Diagnosis and treatment of congenital and hereditary diseases in children (a guide to clinical genetics). M.:"Triad-X". 2004. – 560 p.

6. Bochkov N.P. Clinical genetics. – M.: GEOTAR-MED., 2001. – 448 p.

7. Vakharlovsky V.G., Romanenko O.P., Gorbunova V.N. Genetics in pediatric practice. SPb.: “Phoenix”. 2009. – 288 p.

8. Ginter E.K. Medical genetics. – M.: Medicine. – 2003. – 448 p.

9. Gorbunova V.N. Molecular basis medical genetics. – St. Petersburg: Intermedica. – 1999. – 212 p.

10.Gorbunova V.N., Baranov V.S. Introduction to molecular diagnostics and gene therapy of hereditary diseases. – St. Petersburg: special literature. – 1997. – 287 p.

11. Zayats R.G., Butvilovsky V.E., Rachkovskaya I.V., Davydov V.V. General and medical genetics. Rostov-on-Don: “Phoenix”. 2002. – 320 p.

12. Illarioshkin S.N., Ivanova-Smolenskaya I.A., Markova E.D. DNA diagnostics and medical genetic counseling in neurology. M.: Medical information agency. 2002. – 591 p.

13. Kozlova S.I., Demikova N.S., Semanova E., Blinnikova O.E. Hereditary syndromes and medical genetic counseling. – M.:

Practice. – 1996. – 415 p.

Educational and methodological manual. – 1991. – 95 p.

16. Lilin E.T., Bogomazov E.A., Goffman-Kadoshnikov P.B. Genetics for doctors.

– M.: Medicine. – 1990. – 312 p.

17. Lewin B. Genes. – M.: Mir. – 1987. – 647 p.

18.Mutovin G.R. Fundamentals of clinical genetics. – Higher school, 2001. – 234 p. 19.Murphy E.A., Chase G.A. Fundamentals of medical genetic counseling. M.:

Medicine, 1979.

20. Prikhodchenko N.N., Shkurat T.P. Basics of human genetics. – Rostov-on-

Don: Phoenix. – 1997. – 368 p.

21.Prozorova M.V. Medical genetic counseling for chromosomal diseases and their prenatal diagnosis. – St. Petersburg: MAPO. – 1997. - 15.

22.Prozorova M.V. Chromosomal diseases. – St. Petersburg: MAPO. – 1997. – 23 p. 23. Puzyrev V.P. Genomic research and human diseases. - Sorosovsky

educational magazine. – 1996. - No. 5. – pp. 19-27.

24. Puzyrev V.P., Spepanov V.A. Pathological anatomy of the human genome. – Novosibirsk: Science. – 1997. – 224 p.

25. Repin V.S., Sukhikh G.T. Medical cell biology. – M.: BEBiM. – 1998. – 200 p.

26. Singer M., Berg P. Genes and genomes. – M.: Mir. – 1998. – T.1. – 373 p.

27.Soifer V.N. International Human Genome Project. –

Sorosovsky

educational magazine. – 1996. -

No. 12. – P. 4-11.

28.Human teratology. Ed. 2. –

Ed. G.I. Lazyuk. – M.:

Medicine. –

29. Fovorova O.O. Treatment with genes –

fantasy or reality. –

Sorosovsky

educational magazine. – 1997. -

No. 2. – pp. 21-27.

30.Fogel F., Motulski A. Human Genetics, T.1. – M.: Mir. – 1989. – 312 p. 31.Shabalov N.P. Children's diseases, T.2. – SPb: Peter. 2004. – 736 p. 32. Shevchenko V.A., Topornina N.A., Stvolinskaya N.S. Human genetics. M.:

Humanitarian. ed. VLADOS center. 2002. – 240 p.

1.4 Methods for studying human genetics and diagnostics

hereditary diseases

Chromosomal diseases

Syndromes caused by abnormalities in the autosome system

Down's disease

Edwards syndrome

Patau syndrome

Cry of the cat syndrome

Lejeune's syndrome

Chronic myeloid leukemia

Trisomy 6q syndrome

Retore syndrome

Trisomy 11q syndrome

2.2 Clinical syndromes caused by anomalies

in the sex chromosome system

Shereshevsky-Turner syndrome

Klinefelter syndrome

TrisomyX syndrome

Syndrome 47, XUU

Gene diseases

Phenylketonuria

Galactosemia

Adrenogenital syndrome

Cystic fibrosis

Marfan syndrome

Dystrophinopathies

Prevention of hereditary pathology

Medical genetic counseling

Periconceptional prophylaxis

Preimplantation prophylaxis

Prenatal monitoring

Chorionic villus biopsy

Amniocentesis

Cordocentesis

Prospects of genetics

DNA diagnostics

PRACTICAL LESSON 1

TOPIC: Cytological bases of heredity.

Biochemical bases of heredity.

Hereditary variability.

Lesson duration – 270 minutes

GOAL: To learn:

    Analyze microphotographs and diagrams: 1) phases of mitosis and meiosis, 2) stages of gametogenesis.

    Model implementation processes genetic information: transcriptions, translations.

    Analyze: the consequences of dysregulation of mitosis and gene mutations and the causes that cause them.

As a result of studying the topic, the student should:

be able to:

    conduct surveys and keep records of patients with hereditary pathologies

know:

    biochemical and cytological bases of heredity.

    main types of variability, types of mutations in humans, mutagenesis factors;

Generated general competencies:

OK1. Understand the essence and social significance his future profession, show a steady interest in her.

OK2. Organize your own activities, choose standard methods and ways of performing professional tasks, evaluate their effectiveness and quality.

OK3. Make decisions in standard and non-standard situations and take responsibility for them.

OK4. Search and use information necessary for the effective performance of the professional tasks assigned to him, as well as for his professional and personal development.

OK6. Work in a team and team, communicate effectively
with colleagues, management, consumers.

OK7. Take responsibility for the work of team members (subordinates) and for the results of completing tasks.

OK8. Independently determine the tasks of professional and personal development, engage in self-education, consciously plan and carry out advanced training.

OK12. Organize workplace in compliance with the requirements of labor protection, industrial sanitation, infection and fire safety.

OK13. News healthy image life, engage physical culture and sports to improve health, achieve life and professional goals.

Methodological equipment of the lesson :

    TCO: Laptop for Slide Shows

    Handout:

    Methodological development of a practical lesson for students.

Literature for preparation:

Main:

    Khandogina K.I. Human genetics with the basics of medical genetics: textbook. – M.: GEOTAR-Media, 2013. – 176 p.: with ill.

Additional :

    1. Bochkov N.A. etc. Medical genetics: textbook4 - M.: ACADEMA, 2003

    2. Atlas of Human Chromosomes - Moscow, 1982

    E.K. Timolyanova Medical genetics Rostov-on-Don: Phoenix, 2003.

    N.N. Prikhodchenko, T.P. Shkurat Fundamentals of Human Genetics – Rostov-on-Don: Phoenix, 1997.

    V.A. Orekhova, T.A. Lashkovskaya, M.P. Sheibach Medical Genetics Minsk Higher School 1999.

    N.S. Demidova, O.E. Blinnikova Hereditary syndromes and medical-genetic counseling Leningrad Medicine 1987.

Internet sources:

1. Student advisor – electronic library medical collegewww/ medkollegelib. ru

Lesson plan

    Introductory part– 26 minutes

    Organizational moment;

    Motivation for the lesson;

    Control baseline knowledge.

    Main part – 230 minutes

    Studying the stages of mitosis;

    Study of the stages of meiosis;

Independent work of students on the analysis of mitosis;

    Studying the stages of gametogenesis;

Independent work of students on the analysis of gametogenesis;

    Studying the patterns of implementation of genetic information at the biochemical level.

Independent work to develop skills in modeling and analyzing the processes of replication, transcription, and protein biosynthesis

    Study of hereditary variability

Independent work to develop skills in analyzing hereditary variability.

    Final part – 14 minutes

    Summing up;

    Homework.

Progress of the lesson

    Introductory part

    1. Relevance

Growth and development are associated with cell reproduction (proliferation) multicellular organism, regeneration processes. Disturbances in mitosis underlie the occurrence of somatic mutations - the cause of neoplasms.

Disorders of meiosis (formation of germ cells) predetermine the occurrence of generative mutations, which clinically manifest themselves in the form of hereditary diseases. Chromosome nondisjunction is the cause of genomic mutations

Among the wide variety of molecular components of cells that ensure its functioning, main role in the preservation and transmission of genetic information belongs to nucleic acids. Violation in the structure nucleic acids can lead to pathological changes in the cell - gene mutations.

    1. Incoming control

    What is chromatin, chromosome, chromatid?

    What types of cell division do you know?

    What is interphase?

    Define amitosis.

    Define mitosis.

    Name the phases of mitosis.

    At what stages of mitosis are chromosomes clearly visible?

    What diseases are caused by disruption of the mitosis process?

    Define meiosis.

    What set of chromosomes do sex cells contain?

    What is spermatogenesis and oogenesis?

    Name the periods of gametogenesis.

    During what periods does mitosis occur and during what periods does meiosis occur?

    How is hereditary variation classified?

    What are the causes of gene mutations?

    What are the causes of genomic mutations?

    Main part

    1. Study and analysis of microphotographs, drawings: 1) types of cell division, phases of mitosis and meiosis, 2) stagesdevelopment of human gametogenesis.

Task 1. Cell cycle (CC)

    1. Look at the drawingCC and answer questions

      1. What constitutes the life cycle of a cell (Fig. 1)?

        Name 4 periodsCC;

        Discuss and conclude what the critical point means in the diagram

        What structure do chromosomes have at different periods?CC(Fig. 2)?

        Why interphase takes at least 90% of the timeCC?

    1. Write down in your diary what happens during the presynthetic period (G1), synthetic (S), postsynthetic (G2).

    1. Read the text “Duration of CC in cells of different tissues.” Formulate your conclusions.

“Duration of CC in cells of different tissues”

“Cell cycles (CC) have different durations in the same organism, depending on the tissue. For example, in humans the duration of CC is: for leukocytes 3-5 days, skin epithelium -20-25 days, corneal epithelium -2-3 days, bone marrow cells 8-12 hours, and nerve cells As a rule, they live as long as a person without completing the CC (G1)".

Drawing1 . Cellular (life) cycle.

Task 2. Mitosis. Study and analysis of microphotographs, drawings of mitosis phases.

      1. Consider the diagram of mitosis and answer the questions (Fig. 2)

        1. Why are the stages of prophase, metaphase, anaphase, telophase divided into early and late?

          What is the key process of prophase?

          What is the key metaphase process?

          What is the key process of anaphase?

Drawing2 . Phases of mitosis

Drawing3 . Stages of mitosis (micrograph of mitosis is schematically shown in Fig. 4)

2 . Look at the microphotographs of mitosis (Fig. 4) and answer the questions:

    What is the difference between a schematic representation of mitosis and its microphotograph?

    Which period of mitosis can be identified as the most vulnerable to equal distribution of genetic material?

Drawing4 . Microphotograph of mitosis. The process is shown under a fluorescence microscope. DNA glows blue, and tubulin (and therefore microtubules) glows green:

Task 3. Meiosis. Study and analysis of microphotographs, drawings of meiosis phases.

    Consider the meiosis diagram (Figure 5) and answer the questions:

Drawing 5Meiosis diagram (micrographs and drawings)

    What cells are formed as a result of meiosis?

    How many divisions are there in meiosis?

    What features occur in prophase, metaphase, anaphase, telophase of the 1st division?

    What features occur in prophase, metaphase, anaphase, telophase 2 divisions?

    What is the number of chromosomes at the beginning of meiosis and at the end of 1 division?

    What is the number of chromosomes at the beginning of meiosis and at the end of division 2?

    Look at Fig. 6 and schematically display the stages of meiosis that are missing in Fig. 5. Answer the questions:

    How is metaphase 1 different from metaphase of mitosis?

    What process is shown in Fig. 7?

    What does this process accomplish?

    What are clutch groups?

    What happens when they are violated?

Drawing 6. Mitosis diagram Figure 7. Chromosomes at prophase stage 1

    Read the text “The Meaning of Meiosis.” Formulate your conclusions and write them down.

The meaning of meiosis.

“In organisms that reproduce sexually, the doubling of the number of chromosomes in each generation is prevented, since during the formation of germ cells by meiosis, the number of chromosomes is reduced.

Meiosis creates the opportunity for the emergence of new combinations of genes (combinative variability), as genetically different gametes are formed.

Reducing the number (halving) of chromosomes leads to the formation of “pure gametes” carrying only one allele of the corresponding locus.

The location of the bivalents of the equatorial plate of the spindle in metaphase 1 and chromosomes in metaphase 2 is determined randomly. Subsequent divergence of chromosomes in anaphase leads to the formation of new combinations of alleles in gametes.

Independent chromosome segregation underliesMendel's third law.

Task 4. Studying the stages of human gametogenesis.

The embryonic epithelial cells in the male and female gonads undergo a series of successive mitotic and meiotic divisions called gametogenesis.

Figure 8. Scheme of gametogenesis

    Consider the diagram of the main stages of spermatogenesis and oogenesis in Fig. 7 and answer the questions.

    What are the stages of gametogenesis?

    What division occurs during the reproduction stage?

    What division occurs during the growth stage? What processes take place at this stage?

    What are the resulting cells called? Determine the set of chromosomes.

    What divisions occur during the maturation stage? What is the set of chromosomes of oocytes and spermatocytesII-th order?

    Read the text “Oogenesis.” Briefly write down the features of oogenesis. Answer the questions:

    How many times does the female body go through the reproductive stage?

    When does oocyte formation end?I-th order?

    What features does the period of oocyte maturation have?II-th order?

    Find the inaccuracy in the statement of the last paragraph of the text “Oogenesis”. Write down this statement.

    Explain why maternal age is considered one of the main reasons for the occurrence of mutations in germ cells, and, accordingly, the emerging hereditary pathologies in children?

"Oogenesis"

“Unlike the production of sperm, which begins in men only at puberty, the formation of eggs in women begins even before they are born. The breeding period takes place entirely during the embryonic stage of development, approximately 12 weeks, and is completed at the time of birth.

At the age of 12-13, every month one of the 1st order oocytes continues meiosis. The first meiotic division results in two daughter cells. One of them, relatively small, is called the first polar body, and the other, larger, is the 2nd order oocyte.

The second division of meiosis occurs before the metaphase II stage and will continue only after the 2nd order oocyte interacts with the sperm and fertilization occurs.

Thus, strictly speaking, it is not an egg that comes out of the ovary, but a second-order oocyte.

Only after fertilization does it divide, resulting inegg (oregg ) Andsecond polar body . However, traditionally, for convenience, an egg is called a second-order oocyte, ready to interact with a sperm.

Therefore, it is very important for the expectant mother to lead a healthy lifestyle, as it affects the health of not only the unborn child but also future grandchildren.”

2.2. Studying the patterns of implementation of genetic information at the biochemical level.

Drawing 7Diagram of types of nucleic acids

1. Look at Figure 7, 8 and answer the questions:

    1. What nucleic acids do you know and how do they differ?

      What is a DNA molecule?

      What is a DNA monomer?

      What is a nucleotide, their types?

      List the types of RNA and their functions.

Drawing 8Nucleic acid structures

6. How is genetic information deciphered? Draw a simplified diagram of the implementation of hereditary information.

7. What are transcription and translation (Figure 8)?

8. What is a codon?

9. Define genetic code.

10. List the properties of the genetic code.

Drawing 9Broadcast Drawing 10. Sector recording option,

inner circle - 1st base of codon

(from 5" end)

2. Solve problems:

    What changes will occur in the structure of the protein if guanine is included in the TAACAAAAGAACAAAA gene region between 10 and 11 nucleotides, and between13 and 14 are cytosine, and adenine appears at the end? What are the names of what happened?mutations?

    On a fragment of one DNA strand, the nucleotides are located in the sequence AATAGTCATGTGTGATCAG. a) Draw a diagram of a double-stranded DNA molecule, explain what property of DNA you were guided by? b) Write the mRNA on the bottom strand. What is this process called? c) What is the protein structure of the encoded gene.

    The polypeptide consists of the following amino acids: valine - alanine - glycine - lysine - tryptophan - valine - serine - asparagine - glutamic acid. Determine the structure of the DNA section encoding the specified polypeptide.

2.3. Study of hereditary variability

1. Consider the mutation classification scheme in Fig. 11. Define each type.

( Tautomerism (from the Greek ταύτίς - the same and μέρος - measure) is the phenomenon of reversible isomerism, in which two or more isomers easily transform into each other).

Drawing 11Classification of mutations.

2. Read the text. "Philadelphia Chromosome", write down the conclusions

Philadelphia chromosome

“The first described structural genomic rearrangement in somatic cells that causes cancer is the so-called Philadelphia chromosome, which, according to the International Human Cytogenetic Nomenclature, has its own designation - Ph.

This chromosome was named after the city in the USA where its discoverers P. Nowell and D. Hungerford worked, who reported an unusual small chromosome in two patients with chronic myeloid leukemia in 1960. It is now known that the Philadelphia chromosome arises from a reciprocal translocation between chromosomes 9 and 22, and this mutationcauses 95% of cases of chronic myeloid leukemia. This mutation is also one of the most common in adult B-cell acute lymphoblastic leukemia.

Why this happens is unclear, but a factor provoking this has been identified - ionizing radiation."

3. Consider Figure 13, write down mutagenic factors (MF) and mutational changes (MI) in 2 columns, respectively. Complete the MF column with examples

Pyrimidines:C(C),T(T),U(U), purines: A(A),G(G).

Example:

UV irradiation.

Uncontrolled exposure to active solar radiation.

Solarium

Germicidal lamps

1. Formation of T-T dimers. Incorrect recombination: deletions. inserts

Drawing 12Mutagenic factors - consequences of their impact on DNA

3 . Solve problems:

    In a person with cystinuria (a higher than normal number of amino acids in the urine), amino acids are excreted in the urine, which correspond to the following mRNA triplets: UCU, UGU, HCU, GGU, CAG, CGU, AAA. In a healthy person, alanine, serine, glutamic acid and glycine are found in the urine. The excretion of which amino acids in the urine is typical for patients with cystinuria? Write triplets corresponding to the amino acids found in the urine of a healthy person

    The fourth peptide in normal hemoglobin (hemoglobin A) consists of the following amino acids: valine - histidine - leucine - threonine - proline - glutamic acid - glutamic acid - lysine. In a patient with the symptom of splenomegaly and moderate anemia, the following composition of the fourth peptide was found: valine - histidine - leucine - threonine - proline - lysine - glutamic acid - lysine. Determine the changes that occurred in the DNA encoding the fourth hemoglobin peptide after the mutation.

3. Final part – 14 minutes

3.1 . Summing up;

    Final conversation

    Marking

3.2 . Homework.

    Repeat the topics: “Inheritance of traits in monohybrid, dihybrid and polyhybrid crossings. Hereditary properties of blood."

    Prepare answers to the questions:

    What is a gene, allelic genes?

    How are the signs indicated?

    What traits are called dominant and recessive?

    What is genotype, phenotype?

    How are traits inherited in a monohybrid cross?

    How are traits inherited in incomplete dominance?

    What are the principles for classifying hereditary diseases?

    What is the pathology of chromosomal diseases associated with?

    What are the principles for classifying gene diseases?

    Name the types of classification of monogenic diseases.

    What does mono-, di- and polyhybrid crossing mean?

    What do penetrance and expressivity mean?

Page 15

- (demographic aspects), a branch of genetics that studies the phenomena of heredity and variability in humans. Material basis heredity in humans, as in other organisms, are genes located on chromosomes and passed on through generations... ... Demographic Encyclopedic Dictionary

A branch of genetics closely related to anthropology and medicine. G. h. are conventionally divided into anthropogenetics, which studies the heredity and variability of normal characteristics of the human body, and medical genetics (See Genetics ... ...

Federal State budgetary institution Science Institute of Molecular Genetics Russian Academy Sciences (IMG RAS) Founded 1978 Director member. corr. S. V. Kostrov Employees 134 (2 ... Wikipedia

Contents 1 The beginnings of genetics 2 The era of classical genetics 3 The era of DNA ... Wikipedia

ESTABLISHMENT OF THE RUSSIAN ACADEMY OF SCIENCES INSTITUTE OF CYTOLOGY AND GENETICS SIBERIAN BRANCH OF THE RAS (ICIG SB RAS) International name Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences Founded 1957 Director... ... Wikipedia

Contents 1 The beginnings of genetics 2 The era of classical genetics 3 The DNA era 4 The genomic era ... Wikipedia

Federal State Budgetary Institution of Science Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences (ICiG SB RAS) ... Wikipedia

Ethology is a field discipline of zoology that studies animal behavior. The term was introduced in 1859 by the French zoologist I. Geoffroy Saint-Hilaire. Closely related to zoology, evolutionary theory, physiology, genetics, comparative psychology.... ... Wikipedia

- (from the Greek eugenēs of good kind) the doctrine of human hereditary health and ways to improve its hereditary properties, about possible methods of actively influencing the evolution of humanity in order to further improve its nature, about ... ... Great Soviet Encyclopedia

Lyceum information technology No. 1537 Director: TRUNOVA Tatyana Vladimirovna. Type: Lyceum Students: 400 Address: 129347, Moscow, st. Prokhodchikov, 9 (North-Eastern District, metro station "Babushkinskaya") Telephone ... Wikipedia

© Publishing House “SpetsLit” LLC, 2005

Preface

Genetics as the science of the laws of heredity and variability is the basis modern biology, because it determines the development of all other biological disciplines. However, the role of genetics is not limited to the field of biology. Human behavior, ecology, sociology, psychology, medicine - these are far from full list scientific directions, the progress of which depends on the level of knowledge in the field of genetics. Taking into account the “sphere of influence” of genetics, its methodological role is clear.

One of characteristic features modern science is an ever-deepening differentiation and specialization. This process has reached a level beyond which there is already a real threat of loss of mutual understanding even between representatives of the same science. In biology, due to the abundance of special disciplines, centrifugal tendencies are especially acute. Currently, it is genetics that determines the unity of the biological sciences, thanks to the universality of the laws of heredity and fundamental information systematized in the provisions of general genetics. The methodological role of genetics fully applies to all human sciences.

In this regard, I would like to make critical remarks about the teaching of psychogenetics courses in psychological departments of universities. Psychogenetics is one of the most complex and least developed branches of genetics. Its study should be based on fundamental general biological and general genetic training. Otherwise, the course of psychogenetics becomes purely decorative, representing more of a variant of differential psychology rather than genetics, which is what we can observe at the present time. Knowledge of the laws of heredity plays a huge role in psychological education. All human behavior is, to one degree or another, related to phylogenetic heritage. To understand the subtle mechanisms of this relationship, not superficial, but deep knowledge is required.

The methodological role of genetics in education predetermines special requirements for its teaching, which must combine breadth of coverage, scientific depth and accessibility of presentation. This manual adequately examines all sections of the modern science of genetics necessary for understanding human genetics and behavior, so we hope that it will be useful for all students and scientific workers who study these areas. Brief but holistic presentations of the basic principles of genetics are especially needed in psychology departments.

A lot has been published in our country good textbooks And teaching aids on genetics by Russian and foreign authors (Gershenzon S.M., 1983; Ayala F., Kaiger J., 1988; Alikhanyan S.S., Akifev A.P., 1988; Inge-Vechtomov S.G., 1989). Many manuals are focused on human genetics (Fogel F., Motulski A., 1989–1990; Bochkov N. P., 2004). Recently, after a short break, books on genetics are again appearing on the shelves of our stores (Zhimulev I.

F., 2003; Tarantula V.Z., 2003; Grinev V.V., 2006). Such a variety of literature on this topic can only please everyone who is passionate about such a wonderful science as genetics.

Chapter 1. History and significance of genetics

Genetics is the core of biological science. Only within the framework of genetics can the diversity of life forms and processes be comprehended as a single whole.


Genetics studies two inextricable properties of living organisms - heredity and variability. It is currently the basis of modern biology.

1.1. History of genetics

Although genetics as a science is a little over 100 years old, the history of its origins goes back centuries. The history of genetics is not just the history of a specific science, but rather an independent section of biology, where biological, psychological and philosophical problems are intertwined (Gaisinovich A. E., 1988; Zakharov I. P., 1999). This story has moments full of drama. And at present, genetics remains at the forefront of social discourse, giving rise to heated discussions around the problems of determination of behavior, human cloning, genetic engineering. The history of genetics in our country is completely unique, which knows the times of global intervention of ideology in science (Soifer V.N., 1989; Dubinin N.P., 1990).

What is the reason for such an exceptional role of genetics in the life of society? Genetics is the core of modern biology, the basis for understanding such phenomena as life, evolution, development, as well as the nature of man himself. In the history of natural science, the problem of heredity is considered, starting with the works of ancient thinkers. In modern science, it is discussed in detail in the works of such luminaries as C. Linnaeus (1707–1778), J. Buffon (1707–1788), K. F. Wolf (1734–1794), J.-B. Lamarck (1744–1829), C. Darwin (1809–1882), T. Huxley (1825–1895), A. Weisman (1834–1914) and many others. In those days, problems of genetics were considered in terms of issues of hybridization, development, transformism (or, conversely, constancy) of species.

G. Mendel (1822–1884) is considered the founder of genetics, who substantiated the basic laws of heredity. This discovery was not appreciated by his contemporaries, including the leading biologist of that time, K. Nägeli (1817–1891), to whom G. Mendel sent his works for review.

Rediscovery of Mendel's laws by G. de Vries (1848–1935), K. Correns (1864–1933), E. Cermak (1871–1962) in 1900 is considered to be the date of birth of genetics as an independent science. By that time, the scientific community of biologists was ready to accept new concept. The phenomena of mitosis and meiosis have already been discovered, chromosomes and the process of fertilization have been described, and the nuclear theory of heredity has been formed. Ideas inspired by “rediscovered” patterns spread throughout the world with amazing speed. scientific world, served as a powerful impetus for the development of all branches of biology.

The most interesting history of genetics, chronology most important discoveries, biographies of G. Mendel and other outstanding scientists are described in hundreds of books. Described in detail and tragic story genetics in the Soviet Union. Many books are read with unflagging interest and provide irreplaceable material for understanding this science, the relationship between the laws of genetics and the problems of human society.

Let's look at some milestones in the history of genetics

1901 - G. de Vries proposed the first mutation theory.

1903 – W. Sutton (1876–1916) and T. Boveri (1862–1915) put forward the chromosome hypothesis, “linking” Mendelian factors of heredity with chromosomes.

1906 – W. Bateson (1861–1926) coined the term “genetics.”

1907 - W. Bateson described variants of interaction between genes (“hereditary factors”) and introduced the concepts of “complementarity,” “epistasis,” and “incomplete dominance.” He had earlier (1902) introduced the terms “homozygote” and “heterozygote”.

1908 - G. Nilsson-Ehle (1873–1949) explained and introduced the concept of “polymerism,” which denotes the most important phenomenon in the genetics of quantitative traits.

G. Hardy (1877–1947) and V. Weinberg (1862–1937) proposed a formula for the distribution of genes in a population, later known as the Hardy–Weinberg law, a key law of population genetics.

1909 – V. Johannsen (1857–1927) formulated a number of fundamental principles of genetics and introduced the basic terms: “gene”, “genotype”, “phenotype”, “allele”. V. Volterek introduced the concept of “reaction norm,” which characterizes the possible spectrum of manifestation of a gene.

1910 – L. Plate (1862–1937) developed the concept of multiple gene action and introduced the concept of “pleiotropy”.

1912 – T. Morgan (1866–1945) proposed the theory of chromosomal localization of genes. By the mid-1920s, T. Morgan and representatives of his school - A. Sturtevant (1891–1970), K. Bridges (1889–1938), G. Meller (1890–1967) formulated their own version of the gene theory. The gene problem has become the central problem of genetics.

1920 – G. Winkler introduced the term “genome”. Subsequently, the development of this concept became a new stage in the development of genetics.

N.I. Vavilov (1887–1943) formulated the law of homologous series of hereditary variability.

1921 - L. N. Delaunay (1891–1969) proposed the term “karyotype” to designate the totality of the chromosomes of an organism. The term “idiogram”, previously proposed by S. G. Navashin (1857–1930), later began to be used for standardized karyotypes.

1926 – N.V. Timofeev-Resovsky (1900–1981) developed the problem of the influence of the genotype on the manifestation of a trait and formulated the concepts of “penetrance” and “expressivity”.

1927 - G. Möller receives mutations artificially under the influence of radioactive radiation. He received the 1946 Nobel Prize for his evidence of the mutational effect of radiation.

1929 – A. S. Serebrovsky (1892–1948) first demonstrated the complex nature of the gene and showed that the gene is not a unit of mutation. He also formulated the concept of “gene pool”.

1930–1931 – D. D. Romashov (1899–1963), N. P. Dubinin (1907–1998), S. Wright (1889–1988), R. Fisher (1890–1962), J. Haldane (1860–1936) developed theoretical directions of population genetics and put forward the position of genetic drift.

1941 – J. Beadle (1903–1989) and E. Tatum (1909–1975) formulate the fundamental position: “one gene, one enzyme” (Nobel Prize 1958).

1944 – O. Avery (1877–1955), K. McLeod (1909–1972), M. McCarthy proved the genetic role of DNA in experiments on the transformation of microorganisms. This discovery symbolized the beginning of a new stage - the birth of molecular genetics.

1946 – J. Lederberg, E. Tatum, M. Delbrück (1906–1981) described genetic recombination in bacteria and viruses.

1947 - B. McClintock (1902–1992) first described migrating genetic elements (this outstanding discovery was noted Nobel Prize only in 1983).

1950 – E. Chargaff showed the correspondence of purine and pyrimidine nucleotides in the DNA molecule (Chargaff’s rule) and its species specificity.

1951 – J. Lederberg and his colleagues discovered the phenomenon of transduction, which later played a key role in the development of genetic engineering.

1952 – A. Hershey (1908–1997) and M. Chase showed the decisive role of deoxyribonucleic acid in viral infection, which was the final confirmation genetic significance DNA.

1953 - J. Watson and F. Crick proposed a structural model of DNA. This date is considered the beginning of the era of modern biology.

1955 – S. Ochoa (1905–1993) isolated the enzyme RNA polymerase and was the first to synthesize RNA in vitro.

1956 – A. Kornberg isolated the enzyme DNA polymerase and carried out the process of DNA replication in the laboratory.

1957 – M. Meselson and F. Stahl proved the semi-conservative mechanism of DNA replication. t-RNA was discovered in the laboratory of M. Hoagland.

1958 – F. Crick formulated the “central dogma molecular biology».

1960 - M. Nirenberg, J. Mattei, G. Korana began research on deciphering the genetic code. The work (involving several research groups) was completed in 1966. The compilation of the code dictionary was one of the largest scientific achievements in the history of mankind.

1961 – F. Jacob and J. Monod (1910–1976) formulated the operon theory - the theory of genetic regulation of protein synthesis in bacteria.

1962 - J. Gurdon first obtained cloned vertebrates.

1965 – R. Holley (1922–1993) discovered the structure of t-RNA.

1969 - G. Korana synthesized the gene for the first time in the laboratory.

1970 – G. Temin (1934–1994) and D. Baltimore discovered the phenomenon of reverse transcription.

1972 – P. Berg obtained the first recombinant DNA molecule. This date is considered the birth date of genetic engineering.

1974 – R. Kornberg, A. Olins, D. Olins formulated the theory of nucleosome organization of chromatin.

1975 – On the initiative of a group of scientists led by P. Berg (“Berg Committee”), an International Conference on Ethical Issues of Genetic Engineering was held in Asilomar (USA), at which a temporary moratorium on a number of studies was declared.

The moratorium did not stop work on genetic engineering, and in subsequent years this area actively developed, and a new direction was born - biotechnology.

1976 - D. Bishop and G. Varmus discovered the nature of the oncogene (Nobel Prize 1989).

1977 – W. Gilbert, A. Maxam, F. Senger developed sequencing methods (determining the nucleotide sequence of nucleic acids).

R. Roberts and F. Sharp showed the mosaic (intron-exon) structure of the eukaryotic gene (Nobel Prize 1993).

1978 – Eukaryotic gene transfer carried out (insulin) V bacterial cell, where protein is synthesized on it.

1981 – The first transgenic animals (mice) were produced. The complete nucleotide sequence of the human mitochondrial genome has been determined.

1982 – It is shown that RNA can have catalytic properties, like protein. This fact later promoted RNA to the role of the “first molecule” in theories of the origin of life.

1985 – DNA isolated from an ancient Egyptian mummy was cloned and sequenced.

1988 – On the initiative of US geneticists, the international Human Genome Project was created.

1990 – V. Andersen introduced a new gene into the human body for the first time.

1995 – The first bacterial genome was deciphered. The formation of genomics as an independent branch of genetics.

1997 - J. Wilmut carried out the first successful experiment in cloning mammals ( Dolly the sheep).

1998 – The genome of the first representative of eukaryotes, a nematode, was sequenced Caenorhabditis elegans.

2000 – The sequencing of the human genome is completed.

Genetics is increasingly becoming part of daily life people, largely determining the future of humanity. Research into the human genome is being carried out more and more intensively.

There is no doubt that experiments on “human engineering” will continue, despite any prohibitions. The issues of human cloning, the impact on his genotype, the dangers of modified products are increasingly discussed in the press... It is impossible to predict how all this will affect the fate of humanity.

1.2. Key questions in the history of genetics

In the history of genetics (and its prehistory), a number of key topics can be identified, according to their significance for the scientific worldview and the severity of discussions. In the XVII–XVIII centuries. - this was the problem of “preformationism - epigenesis”, and the camp of preformationists was divided into “ovists” and “animalculists”, depending on whether the female or male sex acted as the carrier of the “embryo”. The problem of “constancy - transformism” was also actively discussed.

The problem of inheritance of acquired characteristics, repeatedly “finally” buried in the history of genetics, has been revived just as many times. In the Soviet Union, discussions around this seemingly private scientific issue acquired at a certain stage in history a huge social resonance, which resulted in numerous human tragedies. This has no analogues in other sciences. In 1958, F. Crick formulated the “central dogma of molecular biology,” according to which the transmission of hereditary information proceeds in the direction from DNA to RNA, and from RNA to proteins. The main point of this scheme is the impossibility of coding from proteins to nucleic acids (although the possibility of transferring information from RNA to DNA is allowed). Therefore, all attempts to revive the hypothesis of the inheritance of acquired characteristics on the basis of new discoveries (and there are such attempts) were rejected by genetics. Currently, this issue is being actively discussed again in connection with recent discoveries.

Of particular interest in the history of genetics was the problem of the carrier of hereditary information. Chromosomes were not immediately recognized as structures responsible for heredity. After this recognition, the role of the molecular carrier of genetic information was more inclined to be given to proteins. DNA seemed too simple a molecule for such an important function. A turn in understanding the role of DNA occurred in 1944 after the experiments of O. Avery, K. McLeod, M. McCarthy on the transformation of characteristics in pneumococci and the identification of the transforming agent as DNA. Although this discovery symbolizes the birth of molecular genetics, it must be said that final confirmation of the role of DNA was obtained only in 1952 after the work of A. Hershey and M. Chase on the study of transduction by bacteriophages.

Acquaintance with history shows that the development of genetics was not strictly progressive, that brilliant discoveries alternated with long delusions, that the greatest scientists were often captive of false beliefs. Founder chromosome theory heredity T. Morgan himself doubted the role of chromosomes for a long time. Opponents of the chromosome theory were W. Batson and V. Johannsen. A. Hershey, who is credited with definitively proving the genetic role of DNA, expressed doubts about this hypothesis.

There are many such examples that can be given. Nature was reluctant to reveal its secrets. Theoretical thought often did not keep up with rapid development experimental studies, continuous complication of the observed patterns. There was also no unanimity in the interpretation of these patterns.

A new era of modern genetics (and all biology) begins in 1953, when J. Watson and F. Crick published a structural model of DNA. But even now, more than half a century later, despite outstanding discoveries and achievements, genetics is full of mysteries. This makes her intriguingly interesting.

1.3. The structure of genetics and its general biological significance

Modern genetics is an extensive tree of derived disciplines. Its specialized sections began to be considered as large independent sciences - human genetics, cytogenetics, molecular genetics, population genetics, immunogenetics, environmental genetics, developmental genetics, genomics, etc.

The tendency towards differentiation of sciences also manifested itself in the direction genetic research of humans: such sections as clinical genetics, human biochemical genetics, human cytogenetics, neurogenetics, etc. have been formed. At the same time, the problem of “narrow specialization” in genetics is not as acute as in other sciences. All specialized genetic disciplines are connected by fundamental information systematized within the framework of general genetics. Moreover, in many ways it is genetics that currently determines the unity of modern biology, therefore the 16th World Genetic Congress in 1988 was held under the motto “Genetics and the unity of biology.”

Without exaggeration, we can say that genetics, to one degree or another, determines the development of all branches of biology and is its methodological basis. The subject of genetics research is heredity and variability - properties that are universal for all living beings. Therefore, the laws of genetics are also universal.

Chapter 2. Molecular basis of heredity

Imagine if you enlarged a person to the size of Great Britain, then the cell would be the size of a factory building. Inside the cell are molecules containing thousands of atoms, including nucleic acid molecules. So, even with such a huge increase, nucleic acid molecules will be thinner than electrical wires.

J. Kendrew, English biochemist, Nobel Prize laureate 1962


Experiments 1940–1950s convincingly proved that it is nucleic acids (and not proteins, as many assumed) that are the carriers of hereditary information in all organisms.

2.1. Nucleic acid structure

Nucleic acids provide various processes for storing, implementing and reproducing genetic information.

Nucleic acids are polymers whose monomers are nucleotides. The nucleotide includes nitrogenous base carbohydrate pentose and the remainder phosphoric acid(Fig. 2.1).

The nitrogenous bases of nucleotides are divided into two types: pyrimidine (consisting of one 6-membered ring) and purine (consisting of two fused 5- and 6-membered rings). Each carbon atom of the base rings has its own specific number. Every carbon atom pentoses also has its own number, but with the index prime ("). In a nucleotide, the nitrogenous base is always attached to the first carbon atom pentoses.

It is the nitrogenous bases that determine the unique structure of DNA and RNA molecules. There are 5 main types of nitrogenous bases found in nucleic acids (purine - adenine and guanine, pyrimidine – thymine, cytosine, uracil) and more than 50 rare (atypical) bases. The main nitrogenous bases are designated by their initial letters: A, G, T, C, U. Most atypical bases are specific to a particular cell type.


Rice. 2.1. Nucleotide structure


The formation of a linear polynucleotide chain occurs through the formation of a phosphodiester bond between the pentose of one nucleotide and the phosphate of another. The pentose phosphate backbone consists of (5 " – 3" ) – connections. The terminal nucleotide at one end of the chain always has a free 5" -group, on the other – 3 " -group.

There are two types of nucleic acids found in nature: DNA and RNA. In prokaryotic and eukaryotic organisms genetic functions perform both types of nucleic acids. Viruses always contain only one type of nucleic acid.

Genetics as the science of the laws of heredity and variability is the basis of modern biology, as it determines the development of all other biological disciplines. However, the role of genetics is not limited to the field of biology. Human behavior, ecology, sociology, psychology, medicine - this is not a complete list of scientific fields, the progress of which depends on the level of genetic knowledge.

Considering the “sphere of influence” of genetics, its methodological role is clear. One of the characteristic features of modern science is ever-deepening differentiation and specialization. This process has reached the point beyond which there is already a real threat of loss of mutual understanding even between representatives of the same science. In biology, due to the abundance of special disciplines, centrifugal tendencies are especially acute. Currently, it is genetics that determines the unity of the biological sciences, thanks to the universality of the laws of heredity and fundamental information systematized in the provisions of general genetics. This methodological role of genetics fully applies to all human sciences.

The self-study guide examines the issues and basic principles of heredity and variability, the structural and functional organization of genetic material, the genetic foundations of evolution, behavior, and development. Issues of human genetics, medical genetics, and psychogenetics are discussed separately.

The manual provides various, often alternative, points of view on unsolved problems, which should show students the absence of beaten paths in science and the need to analyze additional literature.

Each topic includes a description of its content, basic concepts, diagrams, and tables. In tasks for independent work The emphasis is placed on complex and controversial scientific issues. For self-test, each chapter ends control questions. For more in-depth study lists of additional literature are provided. The list of terms provided at the end of the book will allow students to test their knowledge of the material studied.

Topic 1. History and significance of genetics

Genetics is the core of biological science. Only within the framework of genetics can the diversity of life forms and processes be comprehended as a single whole.

F. Ayala, American geneticist

Genetics studies two inextricable properties of living organisms - heredity and variability. It is currently the basis of modern biology.

Genetics as the science of heredity and variability. History of genetics. Main stages and key issues in the history of genetics. The problem of the molecular carrier of heredity. Sections of modern genetics. Connection of genetics with other sciences. Universality of the laws of genetics.

G. Mendel (1822–1884) is considered the founder of genetics, who substantiated the basic laws of heredity. Rediscovery of Mendel's laws by G. de Vries (1848–1935), K. Correns (1864–1933), E. Cermak (1871–1962) in 1900 is considered to be the date of birth of genetics as an independent science.

Let us consider some milestones in the development of genetics in the 20th century.

1901 - G. de Vries proposed the first mutation theory.

1903 – W. Sutton (1876–1916) and T. Boveri (1862–1915) put forward the chromosome hypothesis, “linking” Mendelian factors of heredity with chromosomes.

1905 – W. Bateson (1861–1926) coined the term “genetics.”

1907 - W. Bateson described variants of interaction between genes (“hereditary factors”) and introduced the concepts of “complementarity,” “epistasis,” and “incomplete dominance.” He also earlier (1902) introduced the terms “homozygote” and “heterozygote”.

1908 – G. Nilsson-Ehle (1873–1949) explained and introduced the concept of “polymerism,” the most important phenomenon in the genetics of quantitative traits.

G. Hardy (1877–1947) and V. Weinberg (1862–1937) proposed a formula for the distribution of genes in a population, later known as the Hardy–Weinberg law, a key law of population genetics.

1909 – V. Johannsen (1857–1927) formulated a number of fundamental principles of genetics and introduced the basic concepts of genetic terminology: “gene”, “genotype”, “phenotype”, “allele”.

V. Volterek introduced the concept of “reaction norm,” which characterizes the possible spectrum of manifestation of a gene.

1910 - L. Plate developed the concept of multiple action of genes and introduced the concept of “pleiotropy”.

1912 – T. Morgan (1866–1945) proposed the theory of chromosomal localization of genes. By the mid-20s. T. Morgan and representatives of his school - A. Sturtevant (1891–1970), K. Bridges (1889–1938), G. Meller (1890–1967) formulated their own version of the gene theory. The gene problem has become the central problem of genetics.

1920 – G. Winkler introduced the term “genome”. Subsequently, the development of this concept became a new stage in the development of genetics.

N.I. Vavilov (1887–1943) formulated the law of homologous series of hereditary variability.

1921 - L. N. Delaunay (1891–1969) proposed the term “karyotype” to designate the totality of the chromosomes of an organism. The term “idiogram”, previously proposed by S. G. Navashin (1857–1930), later began to be used for standardized karyotypes.

1926 – N.V. Timofeev-Resovsky (1900–1981) developed the problem of the influence of the genotype on the manifestation of a trait and formulated the concepts of “penetrance” and “expressivity”.

1927 - G. Möller received mutations artificially under the influence of radioactive radiation. For his evidence of the mutational effect of radiation, he was awarded the Nobel Prize in 1946.

1929 – A. S. Serebrovsky (1892–1948) first demonstrated the complex nature of the gene and showed that the gene is not a unit of mutation. He also formulated the concept of “gene pool”.

1930–1931 – D. D. Romashov (1899–1963), N. P. Dubinin (1907–1998), S. Wright (1889–1988), R. Fisher (1890–1962), J. Haldane (1860–1936) developed theoretical directions of population genetics and put forward the position of genetic drift.

1941 – J. Beadle (1903–1989) and E. Tatum (1909–1975) formulated the fundamental position: “one gene, one enzyme” (Nobel Prize 1958).

1944 – O. Avery (1877–1955), C. McLeod (1909–1972), M. McCarthy proved the genetic role of DNA in experiments on the transformation of microorganisms. This discovery symbolized the beginning of a new stage - the birth of molecular genetics.

1946 – J. Ledenberg, E. Tatum, M. Delbrück (1906–1981) describe genetic recombination in bacteria and viruses.

1947 - B. Mack - Clintock (1902–1992) first described migratory genetic elements (this outstanding discovery was awarded the Nobel Prize only in 1983).

1950 – E. Chargaff showed the correspondence of purine and pyrimidine nucleotides in the DNA molecule (Chargaff’s rule) and its species specificity.

1951 – J. Lederberg (with his colleagues) discovered the phenomenon of transduction, which later played a key role in the development of genetic engineering.

1952 – A. Hershey (1908–1997) and M. Chase showed the decisive role of DNA in viral infection, which was the final confirmation of its genetic significance.

1953 – D. Watson and F. Crick proposed a structural model of DNA. This date is considered the beginning of the era of modern biology.

1955 – S. Ochoa (1905–1993) singled out RNA polymerase and was the first to synthesize RNA in vitro.

1956 – A. Kornberg isolated the enzyme DNA polymerase and carried out the process of DNA replication in the laboratory.