American biologist, one of the founders of genetics and chromosome theory heredity. Laureate Nobel Prize Physiology and Medicine for 1933 with the wording: “For discoveries related to the role of chromosomes in heredity.”

Since 1910 Thomas Morgan studied the inheritance of mutations in the Drosophila fly.

(Drosophila is a convenient model object for study because it is cheap, has only 4 pairs of chromosomes and begins to reproduce 12 days after its appearance, producing offspring of 1000 individuals).

“To comprehend the more complex secrets of heredity, it was necessary to find a more convenient object of study than peas or violets. It was found in 1907 by an American Thomas Morgan represented by a small fruit fly - Drosophila. In the cells of her salivary glands, 4 very large chromosomes are visible: they are easy to see even with a magnifying glass , so you can link changes appearance chromosomes (gene variations) with changes in the appearance of the insect itself and variations in the Phenotype. From 1907 to 1926, Morgan and his students observed the heredity of Drosophila - fortunately, it turned out to be as multifaceted and unstable as the heredity of dogs. Morgan was able to distinguish hundreds of variations in the appearance of fruit flies and compiled an Atlas of the location of the corresponding genes in the chromosomes of the fruit fly."

Smirnov S.G., Lectures on the history of science, M., Publishing house MTsNMO, 2012, p. 126.

“The American did an enormous amount for the development of the doctrine of heredity Thomas Morgan, who at first was an equally ardent opponent Mendel and decided to refute it on another object - rabbits. However, the trustees of Columbia University, where Morgan worked, considered the rabbits too expensive; Morgan did not lose heart and used a tiny fruit fly - Drosophila - for experiments.
Drosophila has become a classic object of genetics - a rare case when the stinginess of suppliers provided science with an invaluable service!
The fact is that in a year you can get 25 generations of fruit flies and place their thousands of “herds” on one laboratory table.”

Mednikov B.M., Darwinism in the 20th century, M., “ Soviet Russia", 1975, p. 25.

The effects discovered by Thomas Morgan and his students: G. J. Möller and A. G. Sturtevant explained the mechanism of action of Gregor Mendel's laws.

In 1920 Thomas Morgan wrote: " Mendel left his conclusions in the form of two basic laws: the so-called law of segregation and the law of independent combination of genes. These laws are based on digital data; they are thus quantitative laws and, if desired, can be represented in the form of a mathematical formula. But, despite the fact that their wording is completely accurate, they are still Not give explanations of how the phenomena they control are realized in a living organism. An exclusively mathematical interpretation of the principles of segregation and independent distribution of genes could hardly satisfy botanists and zoologists for a long time. There must inevitably have been a desire to determine where, when and how the process of splitting and reunification takes place, and there must inevitably have been an attempt to reconcile these phenomena with the amazing processes in the germ cells, which have such a universal distribution.”

Thomas Morgan, The Structural Basis of Heredity, quoted in: Life of Science. Anthology of introductions to the classics of natural history / Compiled by: S.P. Kapitsa, M., “Science”, 1973, p. 319.

“After a series of lengthy experiments, Morgan and his colleagues at Columbia University became convinced that chromosomes are indeed directly related to heredity. The results of some of Morgan's experiments seemed to contradict Mendel's law of independent inheritance, according to which each organism has genes that control a particular trait, and the inheritance of one trait is independent of the inheritance of another.
Morgan's team found that some of the signs were apparently related. In other words, their combination occurs more often in descendants than Mendel's statistical laws suggest. Morgan called this phenomenon floor adhesion. The linkage trend told Morgan that the genes appeared to be located in close proximity to each other on the same chromosome.
However, Morgan and his collaborators noted that genes located on the same chromosome were inherited together less frequently than might be expected. Then Morgan began to suspect that chromosomes in a pair could split and exchange sections, thereby allowing for the exchange of genes. This idea was confirmed by microscopic data from intertwined chromosomes. It turns out that the greater the distance between two genes on the same chromosome, the greater the likelihood of a break. If this is the case, then the genes will not be inherited together. Conversely, genes located close to each other on a chromosome are less likely to be separated. Based on this principle, Morgan and his colleagues created “maps” showing the relative locations of genes on fruit fly chromosomes. The idea that genes are localized on the chromosome in a specific linear sequence can be considered one of the main achievements of genetic theory.”

Larina O.V., Gitun T.V., Nobel Prize laureates, “House Slavic book", 2006, p. 372-373.

"Morgan's research was closed There is also a question about the possibility of “nurturing” certain properties in a breed or variety with subsequent transmission to descendants. The only way in which genes can acquire new characteristics was called mutation.
Random and uncontrolled mutations as the only mechanism evolutionary development were perceived by critics - philosophers and religious leaders - as an open and senseless deception of the forces of nature, bringing man down one more step on the ladder leading from heaven. But Morgan was not included in this debate.
In addition, he realized that genetics provided more complete knowledge than eugenics, and left the ranks of this movement in 1914.
The chromosomal theory of heredity won an increasing number of supporters. In 1933 Morgan received highest award for a scientist - the Nobel Prize - for discoveries in the field of physiology and medicine. But in the USSR Not accepted this theory. The country’s leaders did not want to come to terms with the fact that some areas of human nature were beyond their control.”

Travina E., Thomas Morgan: the miracle of the bread, Sat.: Uprising of the Masses, St. Petersburg, “Midgard”, 2005, p. 187.

In the thirties of the last century, N.I. Vavilov wrote: “The laws of Mendel and Morgan formed the basis of modern scientific ideas about heredity, on which breeding work with both plant and animal organisms is based... Among biologists of the 20th century, Morgan stands out as a brilliant experimental geneticist, as a researcher of an exceptional range.”

Thomas Hunt Morgan was born on September 25, 1866 in Lexington, Kentucky. His father was Charlton Hunt Morgan, the US consul in Sicily and a relative of the famous tycoon J.P. Morgan, and his mother was Ellen Kay Morgan. Since childhood, Thomas showed an interest in natural history. He attended the University of Kentucky and graduated in 1886. In the summer of the same year he went to maritime station in Ennisquam on the Atlantic coast, north of Boston. (This was the last year of the local laboratory's existence, and the following year the group moved to Woods Hole.)

In 1887, Thomas entered Johns Hopkins University. In 1888, Morgan began working in Woods Hole, and in the summer of the same year he began working at the state fishery station.

In 1890, Morgan received his doctorate. His dissertation concerned the embryology of a species of sea spider and was based on material he collected at Woods Hole. This work was based on descriptive embryological data with conclusions extending into the field of phylogeny.

Dr. Morgan returned to Woods Hole again. The scientist subsequently spent every summer at this biological station. That same year, Morgan took over as head of department at Bryan Mawr College.

Thomas developed an early interest in experimental embryology. The young scientist spent two summers at the Naples Biological Station: the first time in 1890, and then in 1895. Here he met and became friends with many of those who contributed to the development of experimental embryology - Driesch, Boveri, Dorn and Herbst. Although Morgan was already an experimental embryologist himself, it was this communication that truly directed his interests in this direction. They formed a group of researchers very active both abroad and in the United States.

In 1897, Morgan was elected one of the trustees of Woods Hole Station. At the same time, biologist Wilson from the University of Chicago appeared at the station. It was on his advice that in 1904 Morgan took a professorship at Columbia University. For twenty-four years they worked in very close communication. That same year he married Lillian Vaughan Sampson, a cytologist and former student of his at Bryn Myr. The couple had four children.

Like most biologists and zoologists of the time, Morgan was educated in the field of comparative anatomy and especially in descriptive embryology. The young scientist was also engaged in physiological research. But it was genetics that brought him real fame.

At the end of the nineteenth century, Morgan visited the garden of Hugo de Vries in Amsterdam, where he saw the Defries lines of evening primrose. It was then that he first became interested in mutations. The director of the Woods Hole biological station, Whitman, who was an experimental geneticist, also played a role in Morgan’s reorientation. He devoted many years to studying hybrids between different species of doves and pigeons, but did not want to apply the Mendelian approach. This is understandable, since the pigeons in this case turned out to be, to put it mildly, a mess. Strange signs that did not give a beautiful 3:1 ratio confused Morgan too. For the time being, he saw no way out.

Thus, before 1910, Morgan could rather be considered an anti-Mendelian. That year, the scientist began studying mutations - inherited changes in certain characteristics of the body.

Morgan conducted his experiments on Drosophila, small fruit flies. With his light hand, they became a favorite object of genetic research in hundreds of laboratories. They are easy to get and are found everywhere. They feed on plant sap and all sorts of fruit foulbrood. Their larvae feed on bacteria. The reproductive energy of Drosophila is enormous: from egg to adult – ten days. It is also important for geneticists that Drosophila are subject to frequent hereditary changes. They have few chromosomes - only four pairs. The cells of the salivary glands of fly larvae contain giant chromosomes, which are especially convenient for research.

With the help of Drosophila, genetics has now made many discoveries. The popularity of Drosophila is so great that English a yearbook is published, completely dedicated to her and containing abundant and varied information.

When Morgan began his experiments, he first obtained fruit flies in grocery and fruit shops, fortunately the shopkeepers, who were annoyed by the flies, willingly allowed the eccentric to catch them. Then he and his staff began breeding flies in his laboratory, in a large room dubbed the “fly room.” It was a room the size of thirty-five square meters, which accommodated eight workplaces. There was a place where they cooked food for flies. There were usually at least five workers in the room.

“I’m afraid that I won’t be able to give an idea of ​​the atmosphere that reigned in the laboratory,” recalled one of the scientist’s associates, Alfred Sturtevant. “I think it was something that had to be experienced to be fully appreciated.” One of the greatest advantages of this place was the presence of both Morgan and Wilson. So students specializing in one of them very often saw the other. They complemented each other in a number of ways and were great friends. In our early years at Columbia University, we fed fruit flies bananas, and there was always a big bunch of bananas hanging in the corner of the room. Wilson's room was a few doors down the corridor from ours. He loved bananas very much, so there was another incentive to often visit the “fly room”.

During all this time, Morgan regularly came to Woods Hole. This, however, did not mean a break in experiments with fruit flies. All crops were packed into barrels - large sugar barrels - and sent by express steamer. What you started in New York you ended in Howle, and vice versa. We always came by water: this was the time when the Fall River Line was in operation, and Morgan was always engaged in all sorts of experiments that had nothing to do with work on fruit flies. He raised chickens, rats and mice, and grew various plants. And all this was carried by hand, and loaded onto the Fall River Line ship, and then brought back to New York.

And when Morgan got here, he plunged headlong into working with marine forms, in the embryology of this or that variety, even despite the fact that work with Drosophila was in the meantime actively moving forward. This was Morgan’s style of work - he did not feel happy unless he forged several things out of hot water at the same time.”

The scientist’s success was greatly facilitated by the fact that he, first of all, clearly formulated the initial hypothesis. Now that it was already known that hereditary inclinations are located in chromosomes, it was possible to answer the question: will the numerical patterns established by Mendel always be fulfilled? Mendel quite rightly believed that such patterns would be true if and only if the factors being studied were combined to form zygotes independently of each other. Now, on the basis of the chromosomal theory of heredity, it should be recognized that this is only possible when the genes are located on different chromosomes. But since the number of the latter is small compared to the number of genes, it would be expected that genes located on the same chromosome would pass from gametes to zygotes together. Consequently, the corresponding characteristics will be inherited in groups.

This assumption was tested by Morgan and his collaborators K. Bridges and A. Sturtevant. Soon, a large number of different mutations were discovered in Drosophila, that is, forms characterized by various hereditary characteristics. In normal, or, as geneticists say, wild-type fruit flies, the body color is grayish-yellowish, the wings are gray, the eyes are dark brick-red, the bristles covering the body and the veins on the wings have a very specific arrangement. In mutant flies discovered from time to time, these characteristics were changed: the body, for example, was black, the eyes were white or otherwise colored, the wings were rudimentary, etc. Some individuals carried not one, but several mutations at once: for example, a fly with a black body could, in addition, have rudimentary wings. The variety of mutations allowed Morgan to begin genetic experiments. First of all, he proved that genes located on the same chromosome are transmitted jointly during crossings, that is, they are linked to each other. One linkage group of genes is located on one chromosome. Morgan also received strong confirmation of the hypothesis about the linkage of genes in chromosomes when studying the so-called sex-linked inheritance.

By determining that the gene for Drosophila eye color is localized on the X chromosome, and by monitoring the behavior of the genes in the offspring of certain males and females, Morgan and his collaborators received convincing confirmation of the assumption of gene linkage.

In 1933, Morgan received the Nobel Prize in Physiology or Medicine "for his discoveries concerning the role of chromosomes in heredity." In his Nobel lecture, Morgan stated that the contribution of genetics to medicine is primarily educational. “In the past, the very subject of human heredity was so vague and clogged with all sorts of myths and prejudices that gaining a scientific understanding of the essence of the subject is already an achievement of paramount importance,” he said. Continuing his speech, the scientist suggested that the discovery of the phenomenon of sex linkage may someday be useful for diagnosing genetic diseases.

Morgan came from a prominent family, but was devoid of any arrogance or snobbery. And he, of course, was free from conceit. His background was one of the reasons why he felt completely at home in any company. Both among college presidents and among children.

Morgan's general task, which he sought to solve with his biological activities, was the desire to give a materialistic interpretation of the phenomena of life. He was always reticent about the idea of ​​the existence natural selection, since it seemed to him that this would open the door to explaining biological phenomena in terms that presuppose the presence of a goal. He could be persuaded and convinced that there was absolutely nothing in this idea that was not materialistic, but he never liked it. And he had to be convinced of this again and again every few months.

In 1928, Morgan moved to the California Institute of Technology in order to organize a new biology department. What interested him in this enterprise was the opportunity to organize the department as he wanted, and, moreover, in an institute where physics and chemistry were at their best, where a research atmosphere reigned and where work with students was aimed at raising them to be researchers . Morgan remained at the institute until his death, but he returned regularly to Woods Hole every summer. Over the course of ten years, Morgan's students managed to study three hundred generations of fruit flies.

Thomas Hunt Morgan

Thomas Hunt Morgan is a famous biologist and geneticist, winner of the Nobel Prize in Physiology or Medicine for 1933.
Thomas Hunt Morgan was born in Kentucky on September 25, 1866, into a very distinguished, by American standards, family of a diplomat. Morgan was the great-grandson of composer Francis Scott
Key, author of the US anthem.
In 1886, Thomas Morgan graduated from Kentucky State College and received a bachelor's degree.
In 1887, Morgan entered Johns Hopkins University, and in 1890 he received a doctorate for studying the embryos of sea spiders and in the same year he received an Adam Bruce Fellowship, which allowed him to travel to Europe to the Marine Zoological Laboratory. There he met Hans Drich and Kurt Herbst. It was under the influence of Drich that Morgan began to become interested in experimental embryology.
In 1888–1889 he was engaged in scientific research at the American Fisheries Committee.
In 1891, Thomas Morgan began work as an associate professor of biology at Bryn Myhra Women's College.
In 1901, Morgan's first fundamental work, Regeneration, was published, dedicated to the ability of some species to restore lost body parts.
From 1904 to 1928 he served as professor of experimental zoology at Columbia University ( New York), and from 1928 to 1945 - professor of biology and laboratory director at the California Institute of Technology (Pasadena). IN recent years life acquired a small laboratory in Corona del Mar (California).
In 1904 Morgan married Lillian Vaughan Sampson, a student of his from Bryn Mawr.
When the results of August Weismann became known, who found out that hereditary qualities are transmitted using chromosomes, scientists remembered another scientist - Mendel, who had earlier shown that heredity is transmitted by genes.
At first, Thomas Morgan was skeptical of theories that claimed that chromosomes were carriers of heredity. Likewise, Morgan did not accept Darwin's hypothesis of the accumulation of gradual changes.
In 1902, biologist W. Sutton proposed that units of heredity (genes) are located inside or on the surface of structures in the cell nucleus called chromosomes. Morgan disagreed with this, believing that chromosomes were products of an early stage of organism development. He liked more the idea expressed by the Dutchman Hugo de Vries that new look is formed as a result of mutations. In order to confirm this hypothesis, Thomas Morgan began to look for a convenient object for research. He needed an unpretentious animal with a fast life cycle.
Back in 1900–1901, C.W. Woodworth studied Drosophila as experimental material and was the first to suggest that Drosophila could be used in genetic research, in particular, to study inbreeding. Drosophila has only 4 pairs of chromosomes, it begins to reproduce two weeks after its birth and after 12 days brings offspring of 1000 individuals. It is easy to study during a life span of only 3 months. Plus it costs almost nothing. V.E. Castle and F.E. Lutz also worked with Drosophila, who suggested that Morgan work with the fruit fly.
Since 1908, Morgan began observing Drosophila, which was ideal for studying heredity.
Morgan's fly-room at Columbia University has become legendary. In many jars and bottles, myriads of flies were hatched from larvae and devoted themselves to science. There were always not enough bottles, and, according to the legend, in the early morning on the way to the laboratory, Morgan and his students stole milk bottles, which Manhattan residents put outside their doors in the evening.
By raising flies in glass jars and observing them under a microscope, Morgan discovered the appearance of white-eyed flies, yellow-eyed flies and even pink-eyed flies in addition to the usual red-eyed flies. Over the course of ten years, many different mutants have been discovered in Drosophila.
Morgan crossed flies, observing a huge number of characteristics: eye color, body color, unequal number of bristles, varied shape and size of wings.
Analyzing the results of observations, Thomas Morgan came to the conclusion that a number of qualities are transmitted to descendants in the aggregate. This allowed us to hypothesize that genes are not scattered throughout the cell, but are linked into certain islands.
The fruit fly has only four pairs of chromosomes. Accordingly, Morgan divided the hereditary characteristics of Drosophila into four groups. He came to the conclusion that genes are localized on chromosomes. Each chromosome contains hundreds of genes organized in chains.
Thomas Morgan showed that the greater the distance between two genes, the greater the likelihood of a chain break. This meant that distantly located genes could not be inherited together. Conversely, closely located genes are less likely to be separated. Professor Thomas Morgan and his colleagues found that the magnitude of the linear distance between genes can characterize the degree of linkage of genes. Morgan's discoveries made it possible to claim that heredity can be described by precise quantitative methods. Based on his theory, Thomas Morgan compiled a map of the location of genes in Drosophila chromosomes.
One of important discoveries is the “dependence” of certain mutations on gender (Morgan called this phenomenon “linkage” of genes): white eyes in Drosophila were transmitted only to males. This is how sex chromosomes were discovered.
After processing a large amount of information, Morgan came to interesting conclusions: genes located on the same chromosome were inherited together much less often than might be expected.
Morgan published his first article about Drosophila in 1910, but full force his arguments were outlined in 1915, when his students - Sturtevant, Bridges and Meller, published the book Mechanisms of Mendelian Inheritance, in which they declared that heredity obeys well-defined laws and can be described by precise quantitative methods. This opened the way to the targeted design of new varieties of plants and animal breeds, to a revolution in medicine and agriculture.
Morgan was already approaching fifty and professional recognition was not long in coming. In 1919 he was elected a Foreign Member of the Royal Society of London, and in 1924 he was awarded the Darwin Medal. Morgan became a member of the Academies of Sciences different countries(and also in December 1923 and a member of the USSR Academy of Sciences). In the late 20s, he headed the US National Academy of Sciences. In 1933, Thomas Morgan was awarded the Nobel Prize in Physiology or Medicine for his discoveries related to the role of chromosomes in heredity.
Morgan died in 1945 in Pasadena.

(1866-1945) American biologist, one of the founders of genetics

Thomas Morgan was born in 1866 in Lexington, Kentucky. At the age of twenty, he graduated from the university of his native state, and 5 years later from Johns Hopkins University in Baltimore. He immediately became a professor at Bryn Mawr College, from 1904 to 1928 he worked as a professor at Columbia University, and from 1928 until the end of his life he headed a laboratory at the California Institute of Technology.

Although the first step towards solving the problem of heredity was made by Mendel when he discovered mathematically correct laws for the transmission of individual properties of an organism to offspring, the development of the science of heredity is still associated with the name of Morgan, because it was he who experimentally substantiated the chromosomal theory of heredity.

Morgan and his collaborators, beginning in 1910, provided irrefutable evidence for about 15 years that genes are linearly arranged on chromosomes; established the facts of gene linkage, that is, their joint inheritance in the case of localization on the same chromosome; discovered the principle of independent divergence of each pair of chromosomes into daughter cells, including germ cells.

Luck accompanied the scientist in his research, largely because he managed to find for his experiments living creature, capable of quickly multiplying in a limited space and not requiring large maintenance costs. These conditions were fully met by the well-known and widespread fertile fly Drosophila. In order to find out what characteristics of the parents were inherited by the descendants, they were euthanized. Now nothing prevented me from seeing under a magnifying glass what color the flies’ eyes, back, and what shape their wings or abdomen were. When the flies woke up, new generations were obtained from them and the inheritance of traits was monitored further. By comparing the number of traits that are inherited together, Morgan discovered that each Drosophila chromosome contains a group of genes linked to each other. Thus, it was established that genes are indeed located on chromosomes. :

Morgan's merits are not limited to this alone. The scientist discovered numerous deviations from the rule “one chromosome - one group of jointly inherited traits.” Often, traits that were known to be determined by genes belonging to one group turned out in subsequent generations in a new, unusual “company” of other traits. To explain this “disorder,” Morgan made a completely innovative conclusion for that time: the chromosomes of one pair are capable of exchanging parts with each other. Observations of the behavior of Drosophila chromosomes under a microscope confirmed: at a certain stage of meiosis, two chromosomes come closer, intersect and exchange fragments. In science, this phenomenon is called chromosome crossing, or crossing over.

Morgan and his collaborators imagined chromosomes as necklaces on which beads - genes - were arranged in an orderly manner. This seemingly primitive scheme, especially from the height of our current knowledge, turned out to be very productive. The relative distance between genes on a chromosome was determined by simply counting the frequency of “crossover flies.” This is the name given to fly offspring with characteristics the appearance of which can only be explained by the exchange of corresponding sections between the chromosomes of one pair. These calculations formed the basis for the construction of the first genetic maps relative position on the chromosome of individual genes.

By the early 20s, American scientists had discovered and localized hundreds of Drosophila genes on chromosomes. Nowadays, about 7000 genes are known in this fly, distributed over four chromosomes. The principles discovered by Morgan formed the basis for the compilation of genetic maps in all animal organisms.

For his work on the study of heredity, Thomas Morgan was awarded the Nobel Prize in 1933. For a number of years he was president of the US National Academy of Sciences, and in 1932 he became an honorary member of the USSR Academy of Sciences.

Nobel Prize in Physiology or Medicine, 1933

American zoologist and geneticist Thomas Hunt Morgan was born in Lexington (Kentucky). He was the eldest son and first of three children of diplomat Charlton Hunt Morgan and Ellen Morgan, née Key-Howard, granddaughter of the composer Francis Scott Key, who composed the American national anthem. Since childhood, M. had an interest in natural history and the exact sciences; during summer holidays he enthusiastically explored the countryside, finding and bringing fossils home, amassing a collection various types birds. He later spent two summers conducting geological and biological surveys in the Kentucky mountains while working on a United States Geological Survey expedition.

In 1886 he received a Bachelor of Science degree in State College Kentucky State University (now University). M. was especially interested in the evolution of species. According to the prevailing theory, Darwin's concept of natural selection, within a population there is a certain breadth of variation for each trait. Due to the inheritance of traits within a population, the influence environment ensures such a distribution of characteristics over a number of generations that promotes the survival of individual representatives of the species. At the time when M. completed his first scientific work, practically nothing was known about the actual mechanism of inheritance, and the generally accepted method of studying evolution and heredity was to study the morphology and physiology ( physical fitness and functions) of representatives different types, try to draw a conclusion about the reasons for their similarities or differences. An important part of such research was the study of embryonic development.

In accordance with this practice, M. also began to study morphology and physiology when he entered Johns Hopkins University in 1887. Three years later he received his PhD for research on the embryology of sea spiders. In 1891, he became an associate professor of biology at Bryn Myre College, by now very familiar with comparative and descriptive methods. However, like Darwin's theory, these methods did not provide any explanation for the hereditary transmission of traits. Therefore, M. turned to experimental methods, hoping that accurate and verifiable experimental results would ultimately answer the desired question. In 1897, while studying the ability of some animals to regenerate lost body parts, a trait apparently closely related to the successful survival of the individual, he published the first of a series of papers on the subject, which he continued to develop throughout his life. In his first special work, “Regeneration” (“Regeneration”, 1901), he emphasized the relationship between the phenomena of regeneration and early embryonic development. In 1904, M. was appointed professor of experimental zoology at Columbia University. His early works, done within the walls of this institution, were still devoted to experimental embryology.

M.'s interest in the emerging scientific discipline– genetics – was caused by the fact that in 1900 attention scientific world was again focused on the work of Gregor Mendel on the inheritance of traits in peas, which he published in 1886. Mendel showed that traits are inherited according to strict mathematical laws, indicating the separate independent essence of each trait. In 1902, American biologist William S. Sutton proposed that Mendel's hypothetical “factors”—the units of heredity now called genes—were located within or on the surface of structures in the cell nucleus called chromosomes. However, direct confirmation of the chromosomal theory of heredity was needed. M. was skeptical about the above theory, believing that chromosomes are not carriers of heredity, but are products of the early stages of development. He was also skeptical about Darwin’s idea of ​​“gradual change,” preferring to it the theory of the Dutch botanist Hugo de Vries, who believed that a new species is formed as a result of mutations.

In 1908, M. began a genetic study of the fruit fly Drosophila melanogaster, a small insect ideal for genetic research: the fly had only 4 chromosomes, it began to reproduce 2 weeks after birth, and it was easy to study throughout its life, the duration of which was 3 months. It took millions of fruit flies to grow and study before M. and his colleagues at Columbia University came to the conclusion that chromosomes were indeed directly related to heredity.

The results of some experiments conducted by M. on breeding fruit flies seemed to contradict the Mendelian law of independent inheritance, according to which each organism has genes that control one or another trait, and the inheritance of one trait, such as the sex of an animal, does not depend on the inheritance of another – for example, eye color. The group led by M. found that some signs are obviously still connected. In other words, their combination occurs more often in descendants than Mendel's statistical laws suggest. For example, white-eyedness, a mutant trait, was almost always found only in males. M. called this phenomenon adhesion to the floor. The tendency towards linkage suggested to M. that the genes appear to be located in close proximity to each other on the same chromosome. Four such linked groups of genes were discovered in the fruit fly, which corresponded to its four pairs of chromosomes.

At the beginning of 1912, two Columbia University students, Alfred H. Sturtevant and Calvin B. Bridges, joined the group of researchers working with M. in the “fly room”. Two years later, graduate student Herman J. Moeller followed suit. To their surprise, M. and his colleagues noted that genes located on the same chromosome were inherited together less often than might be expected. Most cells in the body had two chromosomes of each type, and M. suspected that the chromosomes in a pair could split and recombine, thereby allowing for the exchange of genes. This idea was confirmed by data obtained under a microscope of intertwined chromosomes, which, according to the Belgian scientist F.A., who first observed them in 1909. Jansens, could exchange their plots with each other.

The greater the distance between two genes on one chromosome, M. reasoned, the greater the likelihood of a break. If this is the case, then the genes will not be inherited together. Conversely, genes located close to each other on a chromosome are less likely to be separated. Already in 1911, Sturtevan realized that the degree of linkage of two genes in a chromosome can be determined by the linear distance between them. Based on this principle, M. and his colleagues compiled “maps”, showing the relative location of genes in the chromosomes of a fruit fly. The idea that genes are localized on a chromosome in a specific linear sequence and, further, that the basis of linkage is the proximity of two genes on a chromosome can be considered one of the main achievements of genetic theory. In 1915, M., Bridges, Sturtevant and Möller reported their research in the book “The Mechanism Heredity”, showing that heredity has well-defined laws and can be described by precise quantitative methods.

In 1928, M. left Columbia College to help organize the biological department at the California Institute of Technology (Caltech) in Pasadena. Several of his former students and employees moved with him to the new institution, which allowed him to assemble an extraordinary team of researchers. The work carried out by M.'s group and other specialists in Pasadena earned the institute a well-deserved reputation as a leader in the field of experimental biology, which it retained even after M. changed his research topic, focusing mainly on embryology.

M. received the Nobel Prize in Physiology or Medicine in 1933 “for his discoveries related to the role of chromosomes in heredity.” In his Nobel lecture, M. stated that the contribution of genetics to medicine is primarily of a purely educational nature. “In the past, the very subject of human heredity was so vague and clogged with all sorts of myths and prejudices that gaining a scientific understanding of the essence of the subject is already an achievement of paramount importance,” he said. Continuing his speech, M. suggested that the discovery of the phenomenon of sex linkage may someday be useful for diagnosing genetic diseases.

After receiving the Nobel Prize, M. continued to perform administrative work at Caltech, combining it with research on such broad topics as biological regeneration, laws of inheritance in pigeons, secondary sexual characteristics in salamanders and cross-lineage in rare species of mice.

Known as stingy when it came to institute funds, M. was a very generous person in life and often secretly financed the studies of especially gifted students.

In 1904, M. married Lilian Vaughan Sampson, a cytologist, his former student at Bryn Myr; The couple had four children. In 1941, M. received the title of honorary professor of biology at Caltech. Four years later he died in Pasadena from a stomach hemorrhage.

Among M.'s many awards are the Darwin Medal (1924) and the Copley Medal of the Royal Society of London (1939). He was elected a Fellow of the Royal Society of London, National Academy Sciences, American Association for the Advancement of Science, American Philosophical Society, Genetic Society of America and American Naturalist Society.

Nobel Prize laureates: Encyclopedia: Trans. from English – M.: Progress, 1992.
© The H.W. Wilson Company, 1987.
© Translation into Russian with additions, Progress Publishing House, 1992.