Lecture 1.1 The subject and the main tasks of genetics. Milestones of genetics

SCOPE AND MAIN genetics TASKs

1. Subject genetics.

2. Basic concepts of genetics.

3. Place of genetics among the biological sciences. How genetics with other biological sciences.

4. History of Genetics. The origins of genetics. Milestones genetics.

5. Problems and prospects of genetics as a biological science.

1. Genetics (from the Greek. Γενητως - origin) - the science of the laws of heredity and variation characteristics of living organisms, methods of management and organization of hereditary material. Genetics studies the conservation laws, inheritance and variability of genetic information in biological systems.

The main signs of the living beings

Life - "... mode of existence of proteins, essential element of which is a constant interchange with the surrounding external nature, and with the cessation of this metabolism ceases and the life that leads to degradation of the protein. " (By Engels)

Live body - open, self-regulating and self-reproducing system built from biopolymers - proteins and nucleic acids.

Living system - a set of interacting components that provide a new quality, which was not a component.

Signs of living organisms:

1. The ability to exchange materials with the environment, energy exchange.

Processes: nutrition, respiration, excretion

Metabolism provides a constant chemical composition and structure of all parts of the body.

2. Self-reproduction (reproduction or multiplication) and the ability to evolve

Because of this large molecule, cell organelles, cells and organisms themselves are similar in structure to its predecessors (heredity, variability), are subject to change, giving rise to new species

3. Development - the acquisition of new individual characteristics of the organism.

4. Growth - increase in mass due to reproduction.

5. Motion

6. Irritability - selective response to external forcing.

7. Self-regulation - the constancy of structure and chemical composition of the internal environment (homeostasis).

8. Discrete structure

(A kind of fish is, the cell consists of organelles, organelles - from molecules that the body - of bodies). Readability - the basis of structural order.

Signs of living organisms should be considered in the aggregate.

The date of birth of genetics assumed in 1900 when three botany - G. De Vries in Holland, C. Correns in internet connection and E. Tschermak in Austria, who conducted experiments with hibrydizatsiyi plants found independently forgotten work of Mendel and were impressed similarity of the results obtained with them, appreciated the importance of his work and published their data showed that they fully support the findings of Mendel.The term "genetics" to describe the science of heredity and variation of organisms suggested in 1906 the English scientist William Bateson (1861-1926).

2. Heredity - a property of organisms repeated from generation to generation like signs and provide specific nature of individual development in a particular environment. Through heredity parents and offspring have a similar type of metabolism, the chemical composition of tissue, the nature of metabolism, physiological functions, morphological and other features. Each type of organism reproduces itself from generation to generation.

Volatility - a phenomenon opposite to heredity. Volatility is to change hereditary traits, as well as the variability of their manifestations in the process of the interaction of organisms with the environment.

Inheritance - a way of transferring genetic information, which can vary depending on the form of reproduction.

Gene, Allele, Genome, Genotype, Phenotype

Genome - all the genes in an organism, its complete chromosome.

3. Depending on the object of the study classified the genetics of plants, animals, man and others, depending on the methods used in other disciplines - molecular genetics, ecological genetics and others. Ideas and methods of genetics play an important role in medicine, agriculture, microbiological industry, as well as genetic engineering. molekulyarnoї bіologії, іmunologії, i tsitologії Medicine

Sections of Genetics

• Classical genetics,• Population genetics,• Arheo genetics,• Molecular Genetics,• Genomics,• Medical Genetics,• Genetic engineering,• Sports Genetics,• Forensic Genetics,• Forensic Genetics,• Biochemical Genetics,• Human Genetics,• Genetics of Microorganisms,• Plant Genetics,• Evolutionary Genetics,• Biometric genetics,• Ecological Genetics,• Genetics of quantitative traits,• Physiological Genetics,• Psychiatric Genetics,• Genetics of somatic cells,• Genetics of viruses,• Genetics of sex,• Radiation Genetics,• Developmental Genetics,• Functional Genetics,• Genetic Genealogy

Gradually, had accumulated a lot of data on different transmission characteristics from parents to offspring in plants, animals and humans. The first hybrid plants were obtained T. Fairchild (1708) and I. Kelreyterom (1760-1766 years) in carnations and tobacco. English naturalist Andrew T. Knight in 1799 published his work on the hybridization of different forms pea and found it described phenomenon domination gray seeds and purple color of flowers, but do not realize cleavage patterns.

French biologist Sazhre Augustin (1763-1851) conducted his research mainly on plants of the family Cucurbitaceae. He was the first in the history of hybridization began to study the inheritance of certain traits. Crossing various forms of melon, Sazhre identified 5 characteristics and found their alternative pairs (eg, pulp white and yellow, white and yellow seeds, ribs pronounced and unexpressed, etc.), that later made and Mendel. Sazhre first formulated the principle of individual characters and found it their inheritance.

But starting in 1910 the science of heredity captured embryology professor at Columbia University (USA), Thomas Ghent Morgan (1866-1945). Together with its employees Bridjes, Meller, Stertevantom and others - the future Nobel laureate (1933) - Morgan made a good choice of model object of research - fruit fly Drosophila. School Morgan experimentally prove the chromosome theory of heredity, the linear arrangement of genes in the chromosomes and the phenomenon is linked inheritance.

In 1909, Danish biologist Johannsen (1857-1927) introduced a scientific revolution terms "allele" (a gene that determines the sign that monohibrydno inherited, the state of the gene), "gene" (hereditary factors that determine the inherited characteristics of organisms), " genotype "(the sum of all the genes of organisms, its genetic constitution) and" phenotype "(a set of properties and characteristics of an organism at a certain stage of development, which can be described (studied) morphological, anatomical, physiological methods).

The term "gene" was proposed by Hans Winkler in 1920 to describe a set of genes placed in haployinomu set of chromosomes of organisms of one species. The genetic information in cells placed not only in the chromosomes of the nucleus, but nonchromosomal DNA molecules. In bacteria such DNA include plasmids and some moderate viruses in eukaryotic cells - is the DNA of mitochondria, chloroplasts and other organelles of the cell. Thus, in the genome of an organism to understand the total DNA of a haploid set of chromosomes and each nonchromosomal genetic elements that are placed in a separate cell of cell cultures germline multicellular organism.

In 1927 the American geneticist Hermann Muller, spokesman Morgan School for example Drosophila experimentally demonstrated the possibility of artificial mutations under the influence of X-rays, while it is shown that for such influence hundred-fold increased occurrence of mutations in comparison with the natural mutation process that mutations are result of random molecular changes.

In the 1942-1944 biennium Charlotte Auerbach (University of Edinburgh, UK) and Rapoport found mutagenic action of certain chemical compounds (ethylene, hydroxylamine et al.).

In 1946, American scientists Lederberh Teytum and proved the existence of the sexual process in bacteria (Echerichia). The process of transfer of genetic information from one bacterium to another during cell contact was named conjugation. And in 1952 Tsinder and Lederberh discovered the phenomenon of transduction (bacteriophage transfer of genetic material (DNA segments) from one bacterial cell to another, which leads to changes in the hereditary characteristics of cells).

Landmark discovery made in 1953 English. geneticist and biophysicist Francis Crick and American biochemist D. Watson - together they created a model of the structure of DNA (double helix) that is not only possible to explain many of its biological properties, but also launched a new direction in genetics - the branch of molecular genetics.

In 1968, the Quran (USA) synthesized active artificial gene. In 1972, American biochemist Paul Berg with employees received the first recombinant DNA molecule of two different viruses, which investigated the structure of individual genes. These works marked the beginning of the birth of a new field of genetics - genetic engineering - systems of experimental techniques that allow you to create artificial genetic structure in the form of recombinant (hybrid) DNA molecules.

Scientific antropohenetyky (human genetics) originated over 100 years ago and since then has made a difficult path. Simple types of inheritance in humans have been described long before the science of genetics, that is, until 1900, when they were rediscovered Mendel's laws. Thus, already in 1750, the French physician P. Maupertuis described the nature of inheritance bahatopalosti (polydactyly), and its cleavage analysis on this basis in many ways ahead of the opening of Mendel. In 1814, George Adamson described some types of inheritance in children of normal parents who were blood rodychanni.

In the period 1803-1820 he was a few doctors describe inheritance of hemophilia. Swiss ophthalmologist Horner in 1876 described the inheritance of color blindness (color blindness).

As a science, human genetics emerged through the works of Francis Galton (1822-1911). Many scientists believe it along with Mendel one of the founders of the science of genetics in general.

In 1899 F. Galton formulated one of the laws of inheritance (law regression) in which: every deviation from the norm or the parents of average transmitted descendants, but only in partial form. Some of the deviations thus inherited (called regression), the other part disappears without a trace. Then he discovered the law of inheritance in ancestors learned some other patterns of inheritance.

In 1876. F. Galton proposed method blyznyukovyy distinction as inheritance and environment in shaping the body. Originally Galton did not hold distinction between identical twins and dvoyaytsevymy. Only later embryologists have found differences between the two types of twins.

F. Galton introduced the method of identification of a person by his fingerprints, that was the ancestor of fingerprinting and dermatoglyphics. This method of identification was used by the English police to identify criminals and their victims. F. Galton mainly studied the inheritance of quantitative traits of man, determined action of many genes that polygenes.

F. Galton studied the inheritance of intelligence, talent in people. He believed that the special genetic measures can improve the human race. He created a special direction in genetics - eugenics, defined its main purpose - to improve the human and the human race.

A. Gobineau (Gobineau), known for his treatise "Experience at inequalities chelovecheskyh races" (1854), is the ancestor of racism.

London physician A. Harrod (1857 - 1936 years) began to formulate the problem of metabolism in humans with hereditary diseases alkaptonuria. In 1908 formulated his well-known position "at vrozhdennыh defects exchanging substances."

George Beadle, who in 1958 shared the Nobel Prize in Physiology or Medicine with other researchers for their work in the field of biochemical genetics, said that the basis of his hypothesis - "one gene - one enzyme" was actually laid the works of Harrod. Beadle formulated hypothesis the same words as the Harrod.

Further development of Harrod A., J. Beedle and E. Teytum research led to the recognition mechanisms of genes action to the formulation of ideas about the genetic and molecular block of hereditary disease.

It was found that the molecular basis of hereditary diseases is genetic block: loss of synthesis of one enzyme or any other protein, which does not develop character, leads to disruption of the chain of biochemical reactions. The development features, as it turned out, is a result of multi-chain of reactions. If one link breaks the chain, the sign does not develop.

Another section of human genetics is population genetics. In 1908, John Hardy - a mathematician at Cambridge University - and B. Weinberg - a doctor from Stuttgart - independentlyformulated the law of the distribution of traits in the human population.

laid the foundations of population genetics, that bears their name.

Act Hardy - Weinberg was formulated during the study of the distribution of traits in the human population. Another Mendel found that in living beings one of a pair of contrasting traits may dominate over another (recessive) trait.Then, in the early stages of mendelism development, some scientists believed that the dominant trait in the population should displace recessive trait. Raised the question: "Why are not all people korotkopali?" Hardy and Weinberg analyzed the frequency distribution of dominant and recessive traits and have shown that, in the absence of factors that violate the equilibrium, frequency of genes and traits they control remains unchanged and is determined by the frequency of mutations.

In the 20-30 years of the last century, a number of researchers (R. Fischer and J. Haldane in England; S. Wright in the U.S.; H. Dahlberg in Switzerland; Hohben L. and F. Bernstein in Germany) made major contributions to the theory of evolution in development of statistical methods for human genetics studying. For example, it includes methods of analyzing patterns of inheritance, splitting, immunizations signs and determined the frequency of mutations.

A major contribution to the development problems of general genetics, human genetics and medical genetics in the years made by Soviet scientists MK Koltsov, AS Serebrovsky, YA Filipchenko. These scientists studied the transmission of hereditary information of some spiritual traits of man, fine structure of chromosomes and genes, many involved in the problems of eugenics.

Landsteiner in 1900 discovered human blood groups, which contributed to the formation of new areas of biological sciences - and particularly immunogenetics.

SN Davydenko established a school neurogenetics.

A major contribution to the overall genetics have MP Dubinin, DD Romashov, AA Malinowski, BP Efroimson, NP Barreled, EF Davydenko, LA Badalyan and many other Soviet geneticists.

The great Russian physiologist IP Pavlov realized the necessity of genetics to physiology and medicine. In recognition of the important role of genetics in physiology in the "capital of conditioned reflexes" Koltushi monument was built Mendel. The following words IP Pavlova can be his testament: "Our doctors dolzhnы, kak alphabet nobility Laws heredity. Nadeau in Cornet destroy the transmission generation embryonic disease, pathological genes. "

5. Problems of Genetics:

1. Bases and mechanisms of heredity and inheritance

2. Genome stability

3. Hereditary diseases

4. Methods of diagnosis and prevention of defects, genetic and multifactorial diseases, management of individual development of organisms

5. management of heredity and variability genetic technology to create new plant varieties, animal breeds, strains, cloning of organs and tissues for transplantation to replace damaged, the development of genetic engineering.

Outlooks: identifying key genetic mechanisms of biological systems, including man, development and functioning helps prevent the development of genetic abnormalities as a cause of hereditary diseases, malignant tumors, and the creation of effective methods for their treatment. Studying the genetic mechanisms of development and the inheritance of traits promotes the development of animal breeding and crop production - creating of individuals that are resistant to diseases and adverse environmental conditions.