Gregor Mendel achievements. Scientific activity of Gregor Mendel

The Austro-Hungarian scientist Gregor Mendel is rightfully considered the founder of the science of heredity - genetics. The work of the researcher, "rediscovered" only in 1900, brought posthumous fame to Mendel and served as the beginning of a new science, which was later called genetics. Until the end of the seventies of the XX century, genetics basically moved along the path laid down by Mendel, and only when scientists learned how to read the sequence of nucleic bases in DNA molecules, did they begin to study heredity not by analyzing the results of hybridization, but based on physicochemical methods.

Gregor Johann Mendel was born in Heisendorf in Silesia on July 22, 1822 into a peasant family. In elementary school, he showed outstanding mathematical abilities and, at the insistence of his teachers, continued his education at the gymnasium in the small nearby town of Opava. However, there was not enough money in the family for the further education of Mendel. With great difficulty they managed to scrape together to complete the gymnasium course. The younger sister Teresa came to the rescue: she donated the dowry accumulated for her. With these funds, Mendel was able to study for some more time at university preparation courses. After that, the family's funds dried up completely.

The way out was proposed by professor of mathematics Franz. He advised Mendel to enter the Augustinian monastery in Brno. It was headed at that time by Abbot Cyril Napp, a man of broad views who encouraged science. In 1843, Mendel entered this monastery and received the name Gregor (at birth he was given the name Johann). Through
For four years, the monastery sent the twenty-five-year-old monk Mendel as a teacher in a secondary school. Then, from 1851 to 1853, he studied natural sciences, especially physics, at the University of Vienna, after which he became a teacher of physics and natural science at a real school in the city of Brno.

His teaching activity, which lasted fourteen years, was highly appreciated by both the leadership of the school and the students. According to the memoirs of the latter, he was considered one of the most beloved teachers. For the last fifteen years of his life, Mendel was the abbot of the monastery.

From his youth, Gregor was interested in natural science. More of an amateur than a professional biologist, Mendel was constantly experimenting with various plants and bees. In 1856 he began the classic work on hybridization and analysis of the inheritance of traits in peas.

Mendel worked in a tiny monastery garden, less than two and a half acres. He sowed peas for eight years, manipulating two dozen varieties of this plant, different in flower color and seed type. He did ten thousand experiments. With his zeal and patience, he brought to considerable amazement the partners who helped him in necessary cases - Winkelmeyer and Lilenthal, as well as the gardener Maresh, who was very prone to drinking. If Mendel and
gave explanations to his assistants, it is unlikely that they could understand him.

Slowly life flowed in the monastery of St. Thomas. Gregor Mendel was also slow. Persistent, observant and very patient. Studying the shape of seeds in plants obtained as a result of crossings, in order to understand the patterns of transmission of only one trait ("smooth - wrinkled"), he analyzed 7324 peas. He examined each seed with a magnifying glass, comparing their shape and making notes.

With Mendel's experiments, another countdown began, the main distinguishing feature of which was, again, Mendel's introduction of a hybridological analysis of the heredity of individual traits of parents in offspring. It is difficult to say what exactly made the naturalist turn to abstract thinking, to digress from bare figures and numerous experiments. But it was precisely this that allowed the modest teacher of the monastic school to see a complete picture of the study; to see it only after having had to neglect the tenths and hundredths due to the inevitable statistical variations. Only then did the alternative traits literally “marked” by the researcher reveal something sensational to him: certain types of crossing in different offspring give a ratio of 3:1, 1:1, or 1:2:1.

Mendel turned to the work of his predecessors for confirmation of a hunch that had flashed through his mind. Those whom the researcher considered to be authorities came at different times and each in his own way to a general conclusion: genes can have dominant (suppressive) or recessive (suppressed) properties. And if so, Mendel concludes, then the combination of heterogeneous genes gives the same splitting of features that is observed in his own experiments. And in the very ratios that were calculated using his statistical analysis. “Checking with algebra the harmony” of the changes taking place in the resulting generations of peas, the scientist even introduced letter designations, marking the dominant state with a capital letter, and the recessive state of the same gene with a lower case letter.

Mendel proved that each trait of an organism is determined by hereditary factors, inclinations (later they were called genes), transmitted from parents to descendants with germ cells. As a result of crossing, new combinations of hereditary traits may appear. And the frequency of occurrence of each such combination can be predicted.

Summarized, the results of the scientist's work look like this:

All hybrid plants of the first generation are the same and show the trait of one of the parents;

Among the hybrids of the second generation, plants appear with both dominant and recessive traits in a ratio of 3:1;

The two traits behave independently in the offspring and occur in all possible combinations in the second generation;

It is necessary to distinguish between traits and their hereditary inclinations (plants exhibiting dominant traits may latently carry
the makings of a recessive);

The combination of male and female gametes is random in relation to the inclinations of what characters these gametes carry.

In February and March 1865, in two reports at meetings of the provincial scientific circle, called the Brew Society of Naturalists, one of its ordinary members, Gregor Mendel, reported the results of his many years of research, completed in 1863.

Despite the fact that his reports were rather coldly received by the members of the circle, he decided to publish his work. She saw the light in 1866 in the works of a society called "Experiments on Plant Hybrids."

Contemporaries did not understand Mendel and did not appreciate his work. For many scientists, the refutation of Mendel's conclusion would mean nothing less than the assertion of their own concept, which said that an acquired trait can be "squeezed" into the chromosome and turned into an inherited one. As soon as they did not crush the “seditious” conclusion of the modest abbot of the monastery from Brno, venerable scientists invented all sorts of epithets in order to humiliate and ridicule. But time has decided in its own way.

Yes, Gregor Mendel was not recognized by his contemporaries. Too simple, unsophisticated seemed to them a scheme in which, without pressure and creaking, complex phenomena, which, in the minds of mankind, were the foundation of an unshakable pyramid of evolution, fit in. In addition, there were vulnerabilities in Mendel's concept. So, at least, it seemed to his opponents. And the researcher himself, too, because he could not dispel their doubts. One of the "culprits" of his failures was
hawk.

The botanist Karl von Negeli, a professor at the University of Munich, after reading Mendel's work, suggested that the author check the laws he discovered on a hawk. This small plant was Naegeli's favorite subject. And Mendel agreed. He spent a lot of energy on new experiments. Hawkweed is an extremely inconvenient plant for artificial crossing. Very small. I had to strain my eyesight, and it began to worsen more and more. The offspring obtained from crossing the hawk did not obey the law, as he believed, correct for everyone. Only years after biologists established the fact of a different, non-sexual reproduction of the hawk, the objections of Professor Negeli, Mendel's main opponent, were removed from the agenda. But neither Mendel nor Negeli himself, alas, were already dead.

Very figuratively, the greatest Soviet geneticist Academician B.L. Astaurov, the first president of the All-Union Society of Geneticists and Breeders named after N.I. Vavilova: “The fate of Mendel's classical work is perverse and not alien to drama. Although he had discovered, clearly shown, and to a large extent understood the very general laws of heredity, the biology of that time had not yet matured to the realization of their fundamental nature. Mendel himself foresaw with amazing insight the general validity of the patterns found on peas and received some evidence of their applicability to some other plants (three types of beans, two types of levkoy, corn and nocturnal beauty). However, his persistent and tedious attempts to apply the found patterns to the crossing of numerous varieties and species of hawks did not justify hopes and failed completely. How happy was the choice of the first object (peas), just as unsuccessful was the second. Only much later, already in our century, it became clear that the peculiar patterns of inheritance of traits in the hawk are an exception that only confirms the rule. In Mendel's time, no one could have suspected that the crossings of hawkweed varieties he had undertaken did not actually occur, since this plant reproduces without pollination and fertilization, in a virgin way, through the so-called apogamy. The failure of painstaking and strenuous experiments that caused almost complete loss of vision, the burdensome duties of a prelate that fell on Mendel and advanced years forced him to stop his favorite studies.

A few more years passed, and Gregor Mendel passed away, not anticipating what passions would rage around his name and what glory it would eventually be covered with. Yes, glory and honor will come to Mendel after death. He will leave life without unraveling the secrets of the hawk, which did not “fit” into the laws of uniformity of hybrids of the first generation and the splitting of signs in the offspring that he derived.

It would have been much easier for Mendel if he had known about the work of another scientist Adams, who by that time had published a pioneering work on the inheritance of traits in humans. But Mendel was not familiar with this work. But Adams, on the basis of empirical observations of families with hereditary diseases, actually formulated the concept of hereditary inclinations, noticing the dominant and recessive inheritance of traits in humans. But botanists had not heard of the work of a doctor, and the doctor probably had so much practical medical work that there was simply not enough time for abstract reflection. In general, one way or another, but geneticists learned about Adams's observations only when they began to seriously study the history of human genetics.

Not lucky and Mendel. Too early the great explorer reported his discoveries to the scientific world. The latter was not yet ready for this. Only in 1900, having rediscovered Mendel's laws, the world was amazed at the beauty of the logic of the researcher's experiment and the elegant accuracy of his calculations. And although the gene continued to be a hypothetical unit of heredity, doubts about its materiality were finally dispelled.

Mendel was a contemporary of Charles Darwin. But the article of the Brunnian monk did not catch the eye of the author of The Origin of Species. One can only guess how Darwin would have appreciated Mendel's discovery if he had read it. Meanwhile, the great English naturalist showed considerable interest in the hybridization of plants. Crossing different forms of snapdragon, he wrote about the splitting of hybrids in the second generation: “Why is this so. God knows..."

Mendel died on January 6, 1884, the abbot of the monastery where he conducted his experiments with peas. Unnoticed by his contemporaries, Mendel, however, did not hesitate at all in his rightness. He said: "My time will come." These words are inscribed on his monument, installed in front of the monastery garden, where he set up his experiments.

The famous physicist Erwin Schrodinger believed that the application of Mendel's laws is tantamount to the introduction of the quantum principle in biology.

The revolutionary role of Mendelism in biology became more and more evident. By the early thirties of our century, genetics and the laws of Mendel underlying it had become the recognized foundation of modern Darwinism. Mendelism became the theoretical basis for the development of new high-yielding varieties of cultivated plants, more productive livestock breeds, and useful types of microorganisms. Mendelism gave impetus to the development of medical genetics ...

A memorial plaque has now been erected in the Augustinian monastery on the outskirts of Brno, and a beautiful marble monument to Mendel has been erected next to the front garden. The rooms of the former monastery, overlooking the front garden where Mendel conducted his experiments, have now been turned into a museum named after him. Here are collected manuscripts (unfortunately, some of them perished during the war), documents, drawings and portraits related to the life of the scientist, books that belonged to him with his notes in the margins, a microscope and other tools that he used, as well as those published in different countries. books dedicated to him and his discovery.

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

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

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

However, the Mendel family lived in poverty, and therefore it was not easy to refuse Johann's help. In addition, the boy, helping his father to manage the household, early learned to take care of fruit trees, plants, and besides, he was well versed in flowers. And yet the father wanted to give his son an education. And eleven-year-old Johann, leaving home, continued his studies, first at a school in Lipnik, and then at a gymnasium in Opava. But misfortune seemed to haunt the Mendel family. Four years passed, and Johann's parents could no longer pay for their son's education costs. He had to earn his own living by giving private lessons. However, Johann Mendel did not quit his studies. In his graduation certificate, received in 1840 at the end of the gymnasium, in almost all subjects it was "excellent". Mendel goes to study at Olomouc University, which he failed to finish, because 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 offer of a mathematics teacher to take the veil as a monk of a monastery in the city of Brno.

In 1843, Mendel took the monastic vows and in the Augustinian monastery of Brno received a new name - Gregor. Having become a monk, Mendel was finally freed from the need and constant concern for a piece of bread. In addition, the young man had the opportunity to engage in natural sciences. In 1851, with the permission of the abbot of the monastery, Mendel moved to Vienna and began to study natural sciences at the university, devoting most of his time to physics and mathematics. But he still failed to get a diploma. Even when he entered the monastery, he received a small plot of land on which he was engaged in botany, selection and carried out 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 varieties of peas in the period 1856-1863. They began before the appearance of Ch. Darwin's book "The Origin of Species" and ended 4 years after its publication. Mendel carefully studied this work.

Thoughtfully, with a full understanding of the task, 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 made it possible to strictly control the reproduction processes; thirdly, the hybrids resulting from crossing pea varieties are quite prolific, and this made it possible to follow the course of inheritance of traits in a number of generations. Achieving maximum clarity of experiments, Mendel chose for analysis seven pairs of clearly different features. These differences were as follows: smooth round or wrinkled and irregularly shaped seeds, red or white flower color, tall or low plant, convex or ligamentous pod shape, etc.

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

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

Having examined each trait separately, the scientist was able to accurately calculate which part of the descendants will receive, for example, smooth seeds, and which wrinkled, 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 the flowers, for example, did not affect the color of the fruit, the height of the stem, etc. Each trait is inherited by the plant independently of the other.

Mendel's conclusions 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. The term "chromosome" did not even exist then. He didn't know what a gene was. However, the voids in the knowledge of 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 presentation on plant hybridization. The report was met with puzzled silence. The audience did not ask a single question, it seemed that they did not understand anything in this wise mathematics.

In accordance with the then existing order, 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 concepts that existed at that time. Of course, Mendel understood that his discovery was contrary to the views of other scientists on heredity, which dominated 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 scientists were not up to the quirks of pea offspring and the pedantic algebra of the Austrian naturalist.

Mendel soon abandoned his research on peas. The famous biologist Naegeli advised him to experiment with the hawk plant. These experiments gave strange and unexpected results. Mendel fought in vain over tiny yellowish and reddish flowers. He failed to confirm the results obtained on peas. The insidiousness of the hawk lay in the fact that the development of its seeds occurred without fertilization, and neither G. Mendel nor Nageli knew this.

Even in the hot season of passion for experiments with peas and hawk, he did not forget about his monastic and worldly affairs. In this field, his perseverance 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 admitted that there were much more joyful and bright moments in it. According to him, the scientific work he did brought him great satisfaction. He was convinced that in the near future it would be recognized all over the world. And so it happened, however, after his death.

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

Mendel was not mistaken in his prophecy before his death. After 16 years, on the threshold of the 20th century, the whole 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 Carl 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 Austrian priest and botanist Gregor Johann Mendel laid the foundations for such a science as genetics. He mathematically deduced the laws of genetics, which are now called by his name.

Johann Mendel was born on July 22, 1822 in Heisendorf, Austria. As a child, he began to show interest in the study of plants and the environment. After two years of study at the Institute of Philosophy in Olmütz, Mendel decided to enter a monastery in Brunn. This happened in 1843. During the rite of tonsure as a monk, he was given the name Gregor. Already in 1847 he became a priest.

The life of a clergyman consists not only of prayers. Mendel managed to devote a lot of time to study and science. In 1850, he decided to take the exams for a teacher's diploma, but failed, getting "A" in biology and geology. Mendel spent 1851-1853 at the University of Vienna, where he studied physics, chemistry, zoology, botany and mathematics. Upon his return to Brunn, Father Gregor nevertheless began to teach at the school, although he never passed the exam for a teacher's diploma. In 1868 Johann Mendel became abbot.

From 1856, Mendel carried out his experiments, which eventually led to the sensational discovery of the laws of genetics, in his small parish garden. It should be noted that the environment of the holy father contributed to scientific research. The fact is that some of his friends had a very good education in the field of natural science. They often attended various scientific seminars in which Mendel also participated. In addition, the monastery had a very rich library, of which, naturally, Mendel was a regular. He was very inspired by Darwin's book "The Origin of Species", but it is known for certain that Mendel's experiments began long before the publication of this work.

On February 8 and March 8, 1865, Gregor (Johann) Mendel spoke at meetings of the Natural History Society in Brunn, where he spoke about his unusual discoveries in a still unknown area (which would later become known as genetics). Gregor Mendel set up experiments on simple peas, however, later the range of experimental objects was significantly expanded. As a result, Mendel came to the conclusion that the various properties of a particular plant or animal do not just appear out of thin air, but depend on "parents". Information about these hereditary properties is transmitted through genes (a term coined by Mendel, from which the term "genetics" is derived). As early as 1866, Mendel's book Versuche uber Pflanzenhybriden (Experiments with Plant Hybrids) was published. However, contemporaries did not appreciate the revolutionary nature of the discoveries of the humble priest from Brunn.

Mendel's scientific research did not distract him from his daily duties. In 1868 he became abbot, tutor of an entire monastery. In this position, he perfectly defended the interests of the church in general and the monastery of Brunn in particular. He was good at avoiding conflicts with the authorities and avoiding excessive taxation. He was very much loved by parishioners and students, young monks.

On January 6, 1884, Father Gregor (Johann Mendel) passed away. He is buried in his native Brunn. Glory as a scientist came to Mendel after his death, when experiments similar to his experiments in 1900 were independently carried out by three European botanists who came to similar results with Mendel.

Gregor Mendel - teacher or monk?

The fate of Mendel after the Theological Institute has already been arranged. Ordained as a priest, the twenty-seven-year-old canon received an excellent parish in Old Brunn. He has been preparing for his Doctor of Divinity exams for a year now, when a major change is taking place in his life. Georg Mendel decides to change his fate rather abruptly and refuses to perform religious service. He would like to study nature and for the sake of this passion he decides to take a place in the Znaim gymnasium, where by this time the 7th grade is opening. He asks for the position of "supplement professor".

In Russia, “professor” is a purely university title, and in Austria and Germany even a first-grader mentor was called that way. The gymnasium suplent is rather, it can be translated as “ordinary teacher”, “teacher's assistant”. This could be a person who was fluent in the subject, but since he did not have a diploma, they hired him rather temporarily.

A document has also been preserved explaining such an unusual decision by Pastor Mendel. This is an official letter to Bishop Count Schafgotch from the abbot of the monastery of St. Thomas, Prelate Nappa.” Your Gracious Episcopal Eminence! By Decree No. Z 35338 of September 28, 1849, the High Imperial-Royal Land Presidium considered it a good thing to appoint Canon Gregor Mendel as a supplement at the Znaim Gymnasium. “... This canon has a God-fearing lifestyle, abstinence and virtuous behavior, his dignity is fully appropriate, combined with great devotion to the sciences ... However, he is somewhat less suitable for caring for the souls of the laity, for as soon as he finds himself at the sickbed , as from the sight of suffering, he is seized with insurmountable confusion, and from this he himself becomes dangerously ill, which prompts me to resign from him the duties of a confessor.

So, in the autumn of 1849, Canon and Supplement Mendel arrives in Znaim in order to take up new duties. Mendel receives 40 percent less than his colleagues who had diplomas. He is respected by his colleagues, his students love him. However, he teaches at the gymnasium not subjects of the natural science cycle, but classical literature, ancient languages ​​and mathematics. Need a diploma. This will allow teaching botany and physics, mineralogy and natural history. There were 2 ways to the diploma. One is to graduate from the university, the other is a shorter way - to pass in Vienna, before a special commission of the imperial ministry of cults and education, examinations for the right to teach such and such subjects in such and such classes.

Mendel's laws

The cytological foundations of Mendel's laws are based on:

Pairings of chromosomes (pairings of genes that determine the possibility of developing any trait)

Features of meiosis (processes occurring in meiosis that provide independent divergence of chromosomes with genes located on them to different pluses of the cell, and then to different gametes)

Features of the fertilization process (random combination of chromosomes carrying one gene from each allelic pair)

Scientific method of Mendel

The main patterns of transmission of hereditary traits from parents to offspring were established by G. Mendel in the second half of the 19th century. He crossed pea plants that differ in individual traits, and on the basis of the results obtained substantiated the idea of ​​the existence of hereditary inclinations responsible for the manifestation of traits. In his works, Mendel applied the method of hybridological analysis, which has become universal in the study of the patterns of inheritance of traits in plants, animals, and humans.

Unlike his predecessors, who tried to trace the inheritance of many traits of an organism in the aggregate, Mendel investigated this complex phenomenon analytically. He observed the inheritance of only one pair or a small number of alternative (mutually exclusive) pairs of traits in varieties of garden peas, namely: white and red flowers; low and high growth; yellow and green, smooth and wrinkled pea seeds, etc. Such contrasting traits are called alleles, and the terms "allele" and "gene" are used as synonyms.

For crosses, Mendel used pure lines, that is, the offspring of one self-pollinating plant, which retains a similar set of genes. Each of these lines did not show splitting of signs. It was also essential in the methodology of hybridological analysis that Mendel for the first time accurately calculated the number of descendants - hybrids with different traits, that is, he mathematically processed the results obtained and introduced the symbolism accepted in mathematics to record various crossing options: A, B, C, D and etc. With these letters he designated the corresponding hereditary factors.

In modern genetics, the following symbols are accepted for crossing: parental forms - P; hybrids of the first generation obtained from crossing - F1; hybrids of the second generation - F2, third - F3, etc. The very crossing of two individuals is indicated by the sign x (for example: AA x aa).

Of the many different traits of crossed pea plants in the first experiment, Mendel took into account the inheritance of only one pair: yellow and green seeds, red and white flowers, etc. Such crossing is called monohybrid. If the inheritance of two pairs of traits is traced, for example, yellow smooth pea seeds of one variety and green wrinkled another, then the crossing is called dihybrid. If three or more pairs of traits are taken into account, the cross is called polyhybrid.

Patterns of inheritance of traits

Alleles - denoted by the letters of the Latin alphabet, while Mendel called some signs dominant (predominant) and designated them with capital letters - A, B, C, etc., others - recessive (inferior, suppressed), which he designated with lowercase letters - a, c, c, etc. Since each chromosome (carrier of alleles or genes) contains only one of two alleles, and homologous chromosomes are always paired (one paternal, the other maternal), diploid cells always have a pair of alleles: AA, aa, Aa , BB, bb. Bb, etc. Individuals and their cells that have a pair of identical alleles (AA or aa) in their homologous chromosomes are called homozygous. They can form only one type of germ cells: either gametes with the A allele or gametes with the a allele. Individuals that have both dominant and recessive Aa genes in the homologous chromosomes of their cells are called heterozygous; when germ cells mature, they form gametes of two types: gametes with the A allele and gametes with the a allele. In heterozygous organisms, the dominant allele A, which manifests itself phenotypically, is located on one chromosome, and the recessive allele a, suppressed by the dominant, is in the corresponding region (locus) of another homologous chromosome. In the case of homozygosity, each of the pair of alleles reflects either the dominant (AA) or recessive (aa) state of the genes, which in both cases will show their effect. The concept of dominant and recessive hereditary factors, first applied by Mendel, is firmly established in modern genetics. Later, the concepts of genotype and phenotype were introduced. The genotype is the totality of all the genes that an organism has. Phenotype - the totality of all the signs and properties of the organism, which are revealed in the process of individual development of the given conditions. The concept of phenotype extends to any signs of an organism: features of the external structure, physiological processes, behavior, etc. The phenotypic manifestation of signs is always realized on the basis of the interaction of the genotype with a complex of factors of the internal and external environment.

What contribution to biology, Austrian naturalist, botanist and religious figure, monk, founder of the doctrine of heredity, you will learn from this article.

Gregor Mendel discoveries

The twentieth century was marked by a sensational discovery in the field of biology. Three botanists Cermak, de Vries and Correns stated that 35 years ago, a certain Czech monk and scientist Gregor Mendel, who was unknown to anyone, discovered the laws of inheritance of individual traits.

It is worth noting that Mendel was born into a poor peasant family of a gardener. His parents did not have the means to give their son a decent education. Therefore, the young man graduated only from the gymnasium and dreamed of a university.

One day he went to the abbey and took monastic orders. He pursued one goal - knowledge. The monastery had a rich library, and he got the opportunity to study at the university. In addition, Gregor was fond of biology, and there was a garden near his cell. And he decided to make experiments on crossing plants. Peas acted as a test subject. For his experiments, the monk chose 7 pairs of varieties of this cultivated plant. Each pair of peas had its own difference. For example, the seeds of the first pair had a smooth structure, while the second pair had a wrinkled one; in one, the stem was no more than 60 cm, while in the second it reached 2 m; the color of the flower in one variety was white, and in the other pair - purple.

For the first three years, Mendel planted selected varieties to make sure they were free of impurities. Then the crossbreeding experiments began. During the experiments, he found that one of the plants is dominant and its characteristics suppressed the features of the second plant. Mendel called this process "recessive". So it was opened first law of heredity in biology. The following summer, he crossed the resulting red-colored hybrids with the primary variety of red-colored peas. And what was his surprise when the plant bloomed and the flowers turned out to be white. This phenomenon, the appearance of white color after one generation, Mendel called the "splitting of signs." So was discovered the second law of heredity in biology. Unfortunately, his discovery had no success. Only 140 years later, humanity appreciated his experiments in biology at their true worth.

Gregor Johann Mendel. February 3rd, 2015

Johann Mendel was born (he received the name Gregor when he was tonsured a monk) in 1822 in the small village of Gincice in Moravian Silesia. Almost the entire population of Silesia were Germans. Mendel's parents were also poor German peasants. The future scientist received his primary education in a village school, where there were 80 children in the class. Johann helped his father with the housework, but following in the footsteps of his parents was not his calling. Naturally sensitive and in poor health, he was one of the best students in the school. And he was sent to study further at the school of the Order of Piarists in Lipnik nad Becivou, after which he entered the gymnasium in Opava.
In the countryside and among the PR people, education was free. But in Opava, he already needed money. Several lean years were devastating for his family, and in 1838 an accident happened to Johann's father, he was injured while working in the forest. And here, for the first time, Mendel's instability to stress manifested itself. He was so emotional that in difficult life situations he fell ill. He began to develop depression and neurosis, in which he fainted. But the first difficulties, when at the age of 16 he was left without family support, were overcome. Mendel began to study with less successful students, for which he received some money for food.


In 1840, Johann Mendel entered the Faculty of Philosophy at Olomouc University. Some money was sent to him by his older sister, but they were not even enough to rent a house. Mendel tried to find students, but in Olomouc he had few acquaintances, and without a recommendation, no one wanted a teacher. Poverty and fear that it was impossible to complete his studies again led to a nervous breakdown, and Mendel went to his village for a year to restore his strength and nerves. He was helped to finish his studies in Olomouc by his younger sister, who gave him her dowry.
In 1843 Friedrich Franz, a professor at the University of Olomouc, recommended Mendel to the abbot of the Augustinian monastery of St. Thomas in Brno. Johann Mendel himself later wrote in his biography that “there was no longer any strength, therefore, after graduating from the Faculty of Philosophy, he decided to enter a monastery, which would free him from worries about his daily bread. Circumstances influenced the choice. For a poor person, but striving for knowledge, going to a monastery made it possible to study further, besides engage in self-education and, of course, live in Christian traditions.


Mendel is in the top row, second from the right.
When he was tonsured a monk, he received the name Gregor, and in 1847 he was ordained a priest. Near the temple of the Virgin Mary, where Mendel served, is the hospital of St. Anna. Mendel was supposed to be a pastor there. After 3 months he fell ill. With his sensitivity, it was impossible to constantly see the sick and suffering, he himself was on the verge of a serious nervous illness. The abbot of the monastery F. Napp decided to give Mendel another obedience. Gregor Mendel took up the monastery garden, while studying at the theological faculty and at the same time taking a course on growing fruits and grapes.
In 1849, Mendel was sent to Znojmo to teach Greek, Latin, German, and mathematics at the gymnasium. It turned out that he had a great talent for teaching. And he was sent to the university in Vienna to pass the exam and get a teacher's diploma. But Gregor Mendel did not pass the exam. He flunked natural history and physics.
The abbot did not despair, he decided to help his talented monk and sent him to study at the University of Vienna at the expense of the monastery. Here Mendel first encountered scientific work. After graduating from university, he again tried to pass the exam to get a teacher's diploma. And again unsuccessfully. He was so excited that he fainted. But even without this diploma, he was taken to teach at the State Higher Polytechnic School in Brno, where he taught successfully for 14 years.

At the same time, Mendel began his studies of plants and experiments with the hybridization of peas. He stood at the base of several scientific communities in Brno. Such as the Moravian-Selesian Society for Natural History, the Society of Beekeepers and the Meteorological Society. So it cannot be said that he was engaged only in botany. For several years he conducted meteorological research, measuring air temperature, wind direction, humidity and atmospheric pressure three times a day. He was the first to describe the appearance of a tornado.
Mendel started an apiary in the monastery, studied bees, described some of their diseases, and even tried to breed new species, but was unsuccessful. But experiments with peas led to the discovery of genes and the laws of genetics. In 1862, Gregor Mendel presented his work "Experiments with Pea Hybridization" at the Natural History Society, in which he explained the principles of heredity. But the work was not accepted by the scientific community. The discoveries seemed very new and incredible. Mendel sent his work to various scientists, corresponded with Karl Nagel, professor at the Department of Plant Hybridization at the University of Munich, but it was all in vain. No one took his laws seriously. They were forgotten for several decades. Only at the beginning of the 20th century did his work attract the attention of botanists, who confirmed the discovery of genetic laws by Mendel.
In 1869, Gregor Mendel had to stop experiments with plants, his eyesight began to fall incredibly quickly. And yes, there were other problems. In 1868 Abbot F. Napp died, and Gregor Mendel was chosen as the next abbot of the Augustinian monastery. I had to deal with more problems of the monastery. In 1872, Emperor Franz Joseph awarded Gregor Mendel with a cross, an order established by the emperor for services to society and the church. In general, despite the fact that his work on genetics was not accepted by the scientific community, Mendel enjoyed great prestige as an educated, intelligent and incredibly decent person. It got to the point that in 1881 the Augustinian abbot Mendel was elected director of the Mortgage Bank.

Gregor Mendel's earthly life ended in 1884. On January 6, he died of a lung infection. It seemed that the whole city came to bury the outstanding scientist, the abbot beloved by the monks and just a kind and decent person. The funeral mass in the cathedral of the Old Brno Monastery was conducted by Leoš Janáček. And they buried Gregor Mendel in the same way as all Augustinian monks are buried: in a common tomb in the central Brno cemetery.

In 1910, on the square in front of the monastery, which now bears the name of Gregor Mendel, a monument was erected by Theodor Harlemont. True, after the Second World War, the monument was removed outside the gates of the monastery, then it was not customary to remind that an outstanding scientist, the founder of genetics, was a monk. They tried to convince everyone that faith in God and science are not compatible. Gregor Mendel completely breaks the stereotypes that many people still have.
It would seem that now it is possible to return the monument to its original place, but for some reason the city hall is in no hurry to do this. “This is a paradox,” says the abbot of the monastery Lukasz Martinets, “the more famous a person is in the world, the less interesting he is, as it were, for the city where he lived. When, finally, a society begins to respect its history and the people who left an important mark on it, then it will be possible to say that it develops spiritually and culturally.”