Genetics -the science of the laws of heredity and variability. The main task of genetics is to study the following problems:

1. Storage of hereditary information.

2. The mechanism of transmission of genetic information from generation to generation of cells or organisms.

3. Implementation of genetic information.

Changes in genetic information (study of types, causes and mechanisms of variability).

Development of methods for using genetic engineering to obtain highly efficient producers of various biologically active compounds, and in the future, the introduction of these methods into the genetics of plants, animals and even humans. The methods used in genetics are varied, but the main one is hybridological analysis, that is, crossing followed by genetic analysis of the offspring. It is used at the molecular, cellular (somatic cell hybridization) and organismal levels. In addition, depending on the level of research (molecular, cellular, organismal, population), the object being studied (bacteria, plants, animals, humans) and other factors, a wide variety of methods of modern biology, chemistry, physics, and mathematics are used. However, whatever the methods, they are always auxiliary to the main method - genetic analysis. In 1865, the monk Gregor Mendel (who studied plant hybridization in the Augustinian monastery in Brunn (Brno), now in the Czech Republic) announced at a meeting of the local society of naturalists the results of research on the inheritance of traits when crossing peas (work Experiments on plant hybrids was published in the proceedings of the society in 1866). Mendel showed that some hereditary inclinations do not mix, but are transmitted from parents to descendants in the form of discrete (separate) units. The laws of inheritance he formulated were later called Mendel's laws. During his lifetime, his work was little known and was perceived critically (the results of experiments on another plant, night beauty, at first glance, did not confirm the identified patterns, which critics of his observations very willingly took advantage of).

Ticket No. 7

1. The main components of the cell, their functions.

Cell - an elementary unit of structure and vital activity of all organisms (except for viruses, which are often spoken of as non-cellular forms of life), having its own metabolism, capable of independent existence, self-reproduction and development.

All cellular life forms on Earth can be divided into two kingdoms based on the structure of their constituent cells:

Prokaryotes(pre-nuclear) - simpler in structure and arose earlier in the process of evolution;

Eukaryotes(nuclear) - more complex, arose later. The cells that make up the human body are eukaryotic.

The main elements of eukaryotic cells are:Plasma membrane , surrounding each cell, determines its size and ensures the maintenance of significant differences between the cellular contents and the environment.

Membrane serves as a highly selective filter that maintains the difference in ion concentrations on both sides of the membrane and allows nutrients to penetrate into the cell and waste products to exit. Cytoplasm - the contents of a cell that does not include the nucleus, includes the cytosol and organelles, and is limited by the cell membrane. Cytosol - this is the part of the cytoplasm that occupies the space between membrane organelles. It usually accounts for about half of the total volume of the cell. The cytosol contains many intermediate metabolism enzymes and ribosomes. About half of all proteins produced on ribosomes remain in the cytosol as its permanent components. Core contains the bulk of the genome and is the main site of DNA and RNA synthesis.

Cytoplasm surrounding the nucleus consists of the cytosol and the cytoplasmic organelles located in it. Golgi apparatus consists of regular stacks of flattened membrane sacs called Golgi cisternae ; it receives proteins and lipids from the ER and sends these molecules to various points inside the cell, simultaneously subjecting them to covalent modifications. Mitochondria produce most of the ATP used in biosynthetic reactions that require free energy. Lysosomes contain digestive enzymes that destroy waste organelles, as well as particles and molecules absorbed by the cell from the outside through endocytosis. On their way to lysosomes, engulfed molecules and particles must pass through a series of organelles called endosomes.

(1822-1884) Austrian naturalist, founder of the doctrine of heredity

Gregor Johann Mendel was born on July 22, 1822 in the village of Hinchitsy in the territory of modern Czech Republic in a peasant family. His father instilled in him a love of gardening, and Johann retained this love throughout his life.

The future scientist grew up as a smart and inquisitive boy. An elementary school teacher, noticing the extraordinary abilities of his student, often told his father that Johann should continue his studies.

However, Mendel's family lived poorly, and therefore it was not easy to refuse Johann's help. In addition, the boy, helping his father run the household, early learned to care for fruit trees and plants, and in addition, he had a great understanding of flowers. And yet the father wanted to give his son an education. And eleven-year-old Johann, leaving home, continued his studies, first at school in Lipnik, and then at the gymnasium in Opava. But misfortune seemed to follow the Mendel family. Four years passed, and Johann's parents could no longer pay the costs of their son's education. He was forced to earn his own living by giving private lessons. However, Johann Mendel did not give up his studies. His graduation certificate, received in 1840 at the end of the gymnasium, showed “excellent” in almost all subjects. Mendel goes to study at the University of Olomouc, from which he was unable to graduate, since the family did not have enough money not only to pay for his son’s education, but also to live. And Mendel agrees with the proposal of the mathematics teacher to become a monk at a monastery in the city of Brno.

In 1843, Mendel became a monk and received a new name in the Augustinian monastery of Brno - Gregor. Having become a monk, Mendel was finally freed from the need and constant worry about a piece of bread. In addition, the young man had the opportunity to study natural sciences. In 1851, with the permission of the abbot of the monastery, Mendel moved to Vienna and began studying natural sciences at the university, devoting most of his time to physics and mathematics. But he still failed to obtain a diploma. Even upon entering the monastery, he received a small plot of land on which he was engaged in botany, selection and conducted his famous experiments on the hybridization of pea varieties. Mendel developed several varieties of vegetables and flowers, such as fuchsia, which was widely known among gardeners of that time.

He conducted experiments on crossing pea varieties in the period 1856-1863. They began before the appearance of Charles Darwin’s book “The Origin of Species” and ended 4 years after its publication. Mendel carefully studied this work.

Deliberately, with full understanding of the task at hand, he chose peas as the object of his experiments. This plant, being a self-pollinator, firstly, is represented by a number of pure-line varieties; secondly, the flowers are protected from the penetration of foreign pollen, which makes it possible to strictly control the reproduction processes; thirdly, the hybrids resulting from crossing pea varieties are quite fertile, and this made it possible to trace the progress of inheritance of traits over a number of generations. Achieving maximum clarity of experiments, Mendel chose seven pairs of clearly distinguishable characteristics for analysis. These differences were as follows: smooth round or wrinkled and irregularly shaped seeds, red or white color of the flower, tall or short plant, convex shape of the pods or laced grains, etc.

With perseverance and conscientiousness, which many researchers can envy, for eight years Mendel sowed peas, cared for them, transferred pollen from flower to flower and, most importantly, constantly counted how many red and white flowers, round and oblong, yellow flowers were produced and green peas.

The study of hybrids revealed a very definite pattern. It turned out that in hybrids, out of a pair of contrasting characters, only one appears, regardless of whether this trait comes from the mother or from the father. Mendel designates them as dominant. In addition, he discovered intermediate manifestations of properties. For example, crossing red-flowered peas with white-flowered peas produced hybrids with pink flowers. However, the intermediate manifestation does not change anything in the laws of splitting. Studying the offspring of hybrids, Mendel found that, along with dominant traits, some plants showed traits of another original parent, which do not disappear in hybrids, but go into a latent state. He called such traits recessive. The idea of ​​the recessiveness of hereditary properties and the term “recessiveness” itself, as well as the term “dominance,” have forever entered genetics.

Having examined each trait separately, the scientist was able to accurately calculate which part of the descendants would receive, for example, smooth seeds and which - wrinkled ones, and established a numerical ratio for each trait. He gave a classic example of the role of mathematics in biology. The numerical ratio obtained by the scientist turned out to be quite unexpected. For every plant with white flowers, there were three plants with red flowers. At the same time, the red or white color of flowers, for example, did not in any way affect the color of the fruit, the height of the stem, etc. Each trait is inherited by the plant independently of the other.

The conclusions that Mendel came to were far ahead of his time. He did not know that heredity is concentrated in the nuclei of cells, or rather, in the chromosomes of cells. At that time, the term “chromosome” did not yet exist. He didn't know what a gene was. However, the gaps in knowledge about heredity did not prevent the scientist from giving them a brilliant explanation. On February 8, 1865, at a meeting of the Society of Naturalists in Brno, the scientist made a report on plant hybridization. The report was met with bewildered silence. The listeners did not ask a single question; it seemed that they did not understand anything in this wise mathematics.

In accordance with the then existing procedures, Mendel's report was sent to Vienna, Rome, St. Petersburg, Krakow and other cities. Nobody paid any attention to him. The mixture of mathematics and botany contradicted all the prevailing concepts at that time. Of course, Mendel understood that his discovery ran counter to the views of other scientists on heredity that were dominant at that time. But there was another reason that pushed his discovery into the background. The fact is that during these years the evolutionary theory of Charles Darwin made its victorious march around the world. And the scientists had no time for the whims of the pea offspring and the pedantic algebra of the Austrian naturalist.

Mendel soon abandoned his research on peas. The famous biologist Nägeli advised him to experiment with the hawkweed plant. These experiments produced strange and unexpected results. Mendel struggled in vain over the tiny yellowish and reddish flowers. He was unable to confirm the results obtained on peas. The cunning of the hawkweed was that the development of its seeds occurred without fertilization, and neither G. Mendel nor Nägeli knew this.

Even during the busy period of his passion for experiments with peas and hawkweed, he did not forget about his monastic and secular affairs. In this field, his persistence and perseverance were rewarded. In 1868, Mendel was elected to the high post of abbot of the monastery, which he held until the end of his life. And although the outstanding scientist lived a difficult life, he gratefully acknowledged that there were much more joyful and bright moments in it. According to him, the scientific work he was engaged in brought him great satisfaction. He was convinced that in the near future it would be recognized throughout the world. And so it happened, however, after his death.

Gregor Johann Mendel died on January 6, 1884. In the obituary, among the many titles and merits of the scientist, there was no mention of the fact that he was the discoverer of the law of heredity.

Mendel was not mistaken in his prophecy made before his death. 16 years later, on the threshold of the 20th century, all biological science was excited by the message about Mendel’s newly discovered laws. In 1900, G. de Vries in Holland, E. Cermak in Australia and Karl Correns in Germany independently rediscovered Mendel's laws and recognized his priority.

The rediscovery of these laws caused the rapid development of the science of heredity and variability of organisms - genetics.

The basic laws of heredity were described by the Czech monk Gregor Mendel more than a century ago, when he taught physics and natural history at a secondary school in Brünn (Brno).

Mendel was engaged in breeding peas, and it is to peas that we owe the scientific luck and rigor of Mendel’s experiments the discovery of the basic laws of heredity: the law of uniformity of first-generation hybrids, the law of segregation and the law of independent combination.

Some researchers distinguish not three, but two of Mendel's laws. At the same time, some scientists combine the first and second laws, believing that the first law is part of the second and describes the genotypes and phenotypes of the descendants of the first generation (F 1). Other researchers combine the second and third laws into one, believing that the “law of independent combination” is in essence the “law of independence of segregation” that occurs simultaneously in different pairs of alleles. However, in Russian literature we are talking about Mendel’s three laws.

G. Mendel was not a pioneer in the field of studying the results of plant crossings. Such experiments had been carried out before him, with the only difference being that plants of different species were crossed. The descendants of such a cross (generation F 1) were sterile, and, therefore, fertilization and development of second generation hybrids (when describing breeding experiments, the second generation is designated F 2) did not occur. Another feature of Domendel's work was that most of the traits studied in different crossing experiments were complex both in terms of the type of inheritance and in terms of their phenotypic expression. Mendel's genius lay in the fact that in his experiments he did not repeat the mistakes of his predecessors. As the English researcher S. Auerbach wrote, “the success of Mendel’s work in comparison with the research of his predecessors is explained by the fact that he possessed two essential qualities necessary for a scientist: the ability to ask nature the right question and the ability to correctly interpret nature’s answer.” First, Mendel used different varieties of ornamental peas within the same genus Pisum as experimental plants. Therefore, the plants that developed as a result of such crossings were capable of reproduction. Secondly, as experimental traits, Mendel chose simple qualitative traits of the “either/or” type (for example, the skin of a pea can be either smooth or wrinkled), which, as it later turned out, are controlled by a single gene. Third, Mendel's real success was that the traits he chose were controlled by genes that contained truly dominant alleles. And finally, intuition prompted Mendel that all categories of seeds of all hybrid generations should be accurately counted, down to the last pea, without limiting ourselves to general statements summing up only the most characteristic results (say, there are more such and such seeds than such and such).

Mendel experimented with 22 varieties of peas that differed from each other in 7 characteristics (color, seed texture, etc.). Mendel carried out his work for eight years and studied 20,000 pea plants. All the pea forms he examined were representatives of pure lines; the results of crossing such plants with each other were always the same. Mendel presented the results of his work in an article in 1865, which became the cornerstone of genetics. It is difficult to say what deserves more admiration in him and his work - the rigor of his experiments, the clarity of his presentation of the results, his perfect knowledge of the experimental material, or his knowledge of the work of his predecessors.

In 1863, Mendel completed his experiments and in 1865, at two meetings of the Brunn Society of Natural Scientists, he reported the results of his work. In 1866, his article “Experiments on plant hybrids” was published in the proceedings of the society, which laid the foundations of genetics as an independent science. This is a rare case in the history of knowledge when one article marks the birth of a new scientific discipline. Why is it considered this way?

Work on plant hybridization and the study of the inheritance of traits in the offspring of hybrids was carried out decades before Mendel in different countries by both breeders and botanists. Facts of dominance, splitting and combination of characters were noticed and described, especially in the experiments of the French botanist C. Nodin. Even Darwin, crossing varieties of snapdragons that differed in flower structure, obtained in the second generation a ratio of forms close to the well-known Mendelian split of 3:1, but saw in this only “the capricious play of the forces of heredity.” The diversity of plant species and forms taken into experiments increased the number of statements, but reduced their validity. The meaning or “soul of facts” (Henri Poincaré’s expression) remained vague until Mendel.

Completely different consequences followed from Mendel’s seven-year work, which rightfully constitutes the foundation of genetics. Firstly, he created scientific principles for the description and study of hybrids and their offspring (which forms to cross, how to conduct analysis in the first and second generations). Mendel developed and applied an algebraic system of symbols and character notations, which represented an important conceptual innovation. Secondly, Mendel formulated two basic principles, or laws of inheritance of traits over generations, that allow predictions to be made. Finally, Mendel implicitly expressed the idea of ​​discreteness and binarity of hereditary inclinations: each trait is controlled by a maternal and paternal pair of inclinations (or genes, as they later came to be called), which are transmitted to hybrids through parental reproductive cells and do not disappear anywhere. The makings of characters do not influence each other, but diverge during the formation of germ cells and are then freely combined in descendants (laws of splitting and combining characters). The pairing of inclinations, the pairing of chromosomes, the double helix of DNA - this is the logical consequence and the main path of development of genetics of the twentieth century based on the ideas of Mendel.

The name of the new science – genetics (Latin “relating to origin, birth”) – was proposed in 1906 by the English scientist W. Bateson. The Dane V. Johannsen in 1909 established in the biological literature such fundamentally important concepts as gene (Greek “genus, birth, origin”), genotype and phenotype. At this stage in the history of genetics, the Mendelian, essentially speculative, concept of the gene as a material unit of heredity, responsible for the transmission of individual characteristics in a number of generations of organisms, was accepted and further developed. At the same time, the Dutch scientist G. de Vries (1901) put forward a theory of variability based on the idea of ​​abrupt changes in hereditary properties as a result of mutations.

Works by T.G. Morgan and his school in the USA (A. Sturtevant, G. Meller, K. Bridges), carried out in 1910-1925, created the chromosomal theory of heredity, according to which genes are discrete elements of thread-like structures of the cell nucleus - chromosomes. The first genetic maps of the chromosomes of the fruit fly were compiled, which by that time had become the main object of genetics. The chromosomal theory of heredity was firmly based not only on genetic data, but also on observations about the behavior of chromosomes in mitosis and meiosis, and about the role of the nucleus in heredity. The successes of genetics are largely determined by the fact that it relies on its own method - hybridological analysis, the foundations of which were laid by Mendel.

Mendelian theory of heredity, i.e. the set of ideas about hereditary determinants and the nature of their transmission from parents to descendants, in its meaning, is directly opposite to Domendelian theories, in particular the theory of pangenesis proposed by Darwin. According to this theory, the characteristics of parents are direct, i.e. from all parts of the body are transmitted to offspring. Therefore, the nature of the descendant's trait must directly depend on the properties of the parent. This completely contradicts the conclusions made by Mendel: the determinants of heredity, i.e. genes are present in the body relatively independently of the body itself. The nature of traits (phenotype) is determined by their random combination. They are not modified by any part of the body and are in a dominant-recessive relationship. Thus, the Mendelian theory of heredity opposes the idea of ​​inheritance of characteristics acquired during individual development.

Mendel's experiments served as the basis for the development of modern genetics - a science that studies two basic properties of the body - heredity and variability. He managed to identify patterns of inheritance thanks to fundamentally new methodological approaches:

1) Mendel chose the subject of his study well;

2) he analyzed the inheritance of individual traits in the offspring of crossed plants that differed in one, two, and three pairs of contrasting alternative traits. In each generation, records were kept separately for each pair of these characteristics;

3) he not only recorded the results obtained, but also carried out their mathematical processing.

The listed simple research techniques constituted a fundamentally new, hybridological method of studying inheritance, which became the basis for further research in genetics.

Gregor Johann Mendel became the founder of the doctrine of heredity, the creator of a new science - genetics. But he was so ahead of his time that during Mendel's life, although his works were published, no one understood the significance of his discoveries. Only 16 years after his death, scientists re-read and comprehended what Mendel wrote.

Johann Mendel was born on July 22, 1822 into a peasant family in the small village of Hinchitsy on the territory of the modern Czech Republic, and then the Austrian Empire.

The boy was distinguished by his extraordinary abilities, and at school he was given only excellent grades, as “the first of those who distinguished himself in the class.” Johann's parents dreamed of bringing their son “into the people” and giving him a good education. This was hindered by extreme need, from which Mendel’s family could not escape.

And yet, Johann managed to finish first the gymnasium, and then two-year philosophical courses. He writes in his short autobiography that he “felt that he could no longer withstand such tension, and saw that after completing his course of philosophical studies he would have to find a position for himself that would free him from the painful worries of his daily bread...”

In 1843, Mendel entered the Augustinian monastery as a novice in Brünn (now Brno). This was not at all easy to do;

withstand severe competition (three people for one place).

And so the abbot - the abbot of the monastery - uttered a solemn phrase, addressing Mendel prostrate on the floor: “Throw off the old man who was created in sin! Become a new person! He tore off Johann's worldly clothes - an old frock coat - and put a cassock on him. According to custom, upon taking monastic orders, Johann Mendel received his middle name - Gregor.

Having become a monk, Mendel was finally freed from eternal need and concern for a piece of bread. He had a desire to continue his education, and in 1851 the abbot sent him to study natural sciences at the University of Vienna. But failure awaited him here. Mendel, who will be included in all biology textbooks as the creator of an entire science - genetics, failed the biology exam. Mendel was excellent at botany, but his knowledge of zoology was clearly weak. When asked to talk about the classification of mammals and their economic importance, he described such unusual groups as “beasts with paws” and “clawed animals.” Of the “clawed animals,” where Mendel included only the dog, wolf and cat, “only the cat is of economic importance,” because it “feeds on mice” and “its soft, beautiful skin is processed by furriers.”

Having failed the exam, upset Meidel abandoned his dreams of obtaining a diploma. However, even without it, Mendel, as an assistant teacher, taught physics and biology at a real school in Brünn.

At the monastery, he began to seriously engage in gardening and asked the abbot for a small fenced plot of land - 35x7 meters - for his garden. Who would have imagined that universal biological laws of heredity would be established in this tiny area? In the spring of 1854, Mendel planted peas here.

And even earlier, a hedgehog, a fox and many mice - gray and white - will appear in his monastic cell. Mendel crossed mice and observed what kind of offspring they got. Perhaps, if fate had turned out differently, opponents would later have called Mendel’s laws not “pea laws”, but “mouse laws”? But the monastery authorities found out about Brother Gregor’s experiments with mice and ordered that the mice be removed so as not to cast a shadow on the reputation of the monastery.

Then Mendel transferred his experiments to peas growing in the monastery garden. Later he jokingly told his guests:

Would you like to see my children?

Surprised guests walked with him into the garden, where he pointed out to them the beds of peas.

Scientific conscientiousness forced Mendel to extend his experiments over eight long years. What were they? Mendel wanted to find out how various traits are inherited from generation to generation. In peas, he identified several (seven in total) clear characteristics: smooth or wrinkled seeds, red or white flower color, green or yellow color of seeds and beans, tall or short plant, etc.

The peas bloomed eight times in his garden. For each pea bush, Mendel filled out a separate card (10,000 cards!), which contained detailed characteristics of the plant on these seven points. How many thousands of times did Mendel transfer the pollen of one flower to the stigma of another with tweezers! For two years, Mendel painstakingly checked the purity of the pea lines. From generation to generation, only the same signs should have appeared in them. Then he began to cross plants with different characteristics to obtain hybrids (crosses).

What did he find out?

If one of the parent plants had green peas, and the second had yellow ones, then all the peas of their descendants in the first generation will be yellow.

A pair of plants with a high stem and a low stem will produce first generation offspring with only a tall stem.

A pair of plants with red and white flowers will produce first generation offspring with only red flowers. And so on.

Perhaps the whole point is from whom exactly - “father” or “mother” - the descendants received their

signs? Nothing like this. Surprisingly, it didn't matter in the slightest.

So, Mendel precisely established that the characteristics of the “parents” do not “merge” together (red and white flowers do not turn pink in the descendants of these plants). This was an important scientific discovery. Charles Darwin, for example, thought differently.

Mendel called the dominant trait in the first generation (for example, red flowers) dominant, and the “receding” trait (white flowers) - recessive.

What will happen in the next generation? It turns out that the “grandchildren” will again “resurface” the suppressed, recessive traits of their “grandparents.” At first glance, there will be unimaginable confusion. For example, the color of the seeds will be “grandfather”, the color of the flowers will be “grandmother”, and the height of the stem will be “grandfather” again. And each plant is different. How to figure all this out? And is this even conceivable?

Mendel himself admitted that resolving this issue “required a certain amount of courage.”

Gregor Johann Mendel.

Mendel's brilliant discovery was that he did not study whimsical combinations of traits, but examined each trait separately.

He decided to accurately calculate which part of the descendants would receive, for example, red flowers, and which – white, and establish a numerical ratio for each trait. This was a completely new approach to botany. So new that it was ahead of the development of science by as much as three and a half decades. And he remained incomprehensible all this time.

The numerical relationship established by Mendel was quite unexpected. For every plant with white flowers, there were on average three plants with red flowers. Almost exactly - three to one!

At the same time, the red or white color of flowers, for example, does not in any way affect the yellow or green color of peas. Each trait is inherited independently of the other.

But Mendel not only established these facts. He gave them a brilliant explanation. From each of the parents, the germ cell inherits one “hereditary inclination” (later they will be called genes). Each of the inclinations determines some characteristic - for example, the red color of flowers. If the inclinations that determine red and white coloration enter a cell at the same time, then only one of them appears. The second one remains hidden. In order for the white color to appear again, a “meeting” of two inclinations of white color is necessary. According to probability theory, this will happen in the next generation

Abbot's coat of arms of Gregor Mendel.

On one of the fields of the shield on the coat of arms there is a pea flower.

once for every four combinations. Hence the 3 to 1 ratio.

And finally, Mendel concluded that the laws he discovered apply to all living things, for “the unity of the plan for the development of organic life is beyond doubt.”

In 1863, Darwin's famous book On the Origin of Species was published in German. Mendel carefully studied this work with a pencil in his hands. And he expressed the result of his thoughts to his colleague at the Brunn Society of Naturalists, Gustav Nissl:

That's not all, there's still something missing!

Nissl was dumbfounded by such an assessment of Darwin’s “heretical” work, incredible from the lips of a pious monk.

Mendel then modestly kept silent about the fact that, in his opinion, he had already discovered this “missing thing.” Now we know that this was so, that the laws discovered by Mendel made it possible to illuminate many dark places in the theory of evolution (see article “Evolution”). Mendel perfectly understood the significance of his discoveries. He was confident in the triumph of his theory and prepared it with amazing restraint. He remained silent about his experiments for eight whole years, until he was convinced of the reliability of the results obtained.

And finally, the decisive day came - February 8, 1865. On this day, Mendel made a report on his discoveries at the Brunn Society of Naturalists. Mendel's colleagues listened in amazement to his report, peppered with calculations that invariably confirmed the ratio of “3 to 1.”

What does all this math have to do with botany? The speaker clearly does not have a botanical mind.

And then, this persistently repeated “three to one” ratio. What are these strange “magic numbers”? Is this Augustinian monk, hiding behind botanical terminology, trying to smuggle something like the dogma of the Holy Trinity into science?

Mendel's report was met with bewildered silence. He was not asked a single question. Mendel was probably prepared for any reaction to his eight-year work: surprise, disbelief. He was going to invite his colleagues to double-check their experiments. But he could not have foreseen such a dull misunderstanding! Really, there was something to despair about.

A year later, the next volume of the “Proceedings of the Society of Naturalists in Brünn” was published, where Mendel’s report was published in an abbreviated form under the modest title “Experiments on plant hybrids.”

Mendel's work was included in 120 scientific libraries in Europe and America. But in only three of them over the next 35 years did someone’s hand open the dusty volumes. Mendel's work was briefly mentioned three times in various scientific works.

In addition, Mendel himself sent 40 reprints of his work to some prominent botanists. Only one of them, the famous biologist from Munich Karl Nägeli, sent a response letter to Mendel. Nägeli began his letter with the phrase that “the experiments with peas are not completed” and “they should be started over.” To begin again the colossal work on which Mendel spent eight years of his life!

Nägeli advised Mendel to experiment with the hawkweed. Hawkweed was Naegeli’s favorite plant; he even wrote a special work about it - “Hawstripes of Central Europe.” Now, if we manage to confirm the results obtained on peas using hawkweed, then...

Mendel took up the hawkweed, a plant with tiny flowers, which was so difficult for him to work with due to his myopia! And what’s most unpleasant is that the laws established in experiments with peas (and confirmed on fuchsia and corn, bluebells and snapdragons) were not confirmed on the hawkweed. Today we can add: and could not be confirmed. After all, the development of seeds in the hawkweed occurs without fertilization, which neither Naegeli nor Mendel knew.

Biologists later said that Naegeli's advice delayed the development of genetics for 40 years.

In 1868, Mendel abandoned his experiments in breeding hybrids. It was then that he was elected to

the high position of abbot of the monastery, which he held until the end of his life. Shortly before his death (October 1

1883), as if summing up his life, he said:

“If I had to go through bitter hours, I had many more wonderful, good hours. My scientific works have given me a lot of satisfaction, and I am convinced that it won’t be long before the whole world recognizes the results of these works.”

Half the city gathered for his funeral. Speeches were made in which the merits of the deceased were listed. But, surprisingly, not a word was said about the biologist Mendel whom we know.

All the papers remaining after Mendel's death - letters, unpublished articles, observation journals - were thrown into the oven.

But Mendel was not mistaken in his prophecy, made 3 months before his death. And 16 years later, when the name of Mendel was recognized by the entire civilized world, descendants rushed to look for individual pages of his notes that accidentally survived the flames. From these scraps they recreated the life of Gregor Johann Mendel and the amazing fate of his discovery, which we described.

Mendel Gregor Johann (07/22/1822, Heinzendorf - 01/06/1884, Brünn), Austrian biologist, founder of genetics. He studied at the schools of Heinzendorf and Lipnik, then at the district gymnasium in Troppau. In 1843 he graduated from philosophical classes at the university in Olmutz and became a monk at the Augustinian Monastery of St. Thomas in Brunn (now Brno, Czech Republic). He served as an assistant pastor and taught natural history and physics at school. In 1851-53 he was a volunteer student at the University of Vienna, where he studied physics, chemistry, mathematics, zoology, botany and paleontology. Upon returning to Brunn he worked as an assistant teacher in a secondary school until 1868, when he became abbot of the monastery.

In 1856, Mendel began his experiments on crossing different varieties of peas that differed in single, strictly defined characteristics (for example, the shape and color of seeds). Accurate quantitative accounting of all types of hybrids and statistical processing of the results of experiments that he conducted for 10 years allowed him to formulate the basic laws of heredity - the splitting and combination of hereditary “factors”. Mendel showed that these factors are separate and do not merge or disappear when crossed. Although when two organisms with contrasting traits are crossed (for example, the seeds are yellow or green), only one of them appears in the next generation of hybrids (Mendel called it “dominant”), the “disappeared” (“recessive”) trait reappears in subsequent generations. Today, Mendel's hereditary "factors" are called genes.

Mendel reported the results of his experiments to the Brunn Society of Naturalists in the spring of 1865; a year later his article was published in the proceedings of this society. Not a single question was asked at the meeting, and the article received no responses. Mendel sent a copy of the article to K. Nägeli, a famous botanist and authoritative expert on problems of heredity, but Nägeli also failed to appreciate its significance. And only in 1900, Mendel’s forgotten work attracted everyone’s attention: three scientists at once, H. de Vries (Holland), K. Correns (Germany) and E. Chermak (Austria), having carried out their own experiments almost simultaneously, became convinced of the validity of Mendel’s conclusions . The law of independent segregation of characters, now known as Mendel's law, laid the foundation for a new direction in biology - Mendelism, which became the foundation of genetics.

Mendel himself, after unsuccessful attempts to obtain similar results by crossing other plants, stopped his experiments and until the end of his life was engaged in beekeeping, gardening and meteorological observations.

Among the scientist’s works is “Autobiography” (Gregorii Mendel autobiographia iuvenilis, 1850) and a number of articles, including “Experiments on plant hybridization” (Versuche uber Pflanzenhybriden, in the “Proceedings of the Brunn Society of Naturalists,” vol. 4, 1866).