Morgan (Morgan), Thomas Hunt( The American zoologist and geneticist Nobel Prize in Physiology or Medicine, 1933)
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Biography Morgan (Morgan), Thomas Hunt
September 25, 1866, Mr.. - December 4, 1945
American zoologist and geneticist Thomas Hunt Morgan was born in Lexington (Kentucky). He was the eldest son and the first of three children of diplomats Charlton Hunt Morgan and Ellen Morgan, born Ki-Howard, granddaughter of the composer Francis Scott Key, who wrote the American national anthem. Since childhood M. an interest in natural history and science, during the summer holidays, he enthusiastically explored the countryside, finding and bringing to the house of fossils, a collection of different species. Later he spent two summers spent geological and biological surveys in the mountains of Kentucky, working in the expedition United States Geological Survey.
In 1886. He received a bachelor of science degree at Kentucky State College (now University). M. particularly interested in the evolution of species. According to prevailing theory, Darwin's concept of natural selection within a population there is a certain latitude variability of each trait. Due to the inheritance of characteristics within a population effect of the environment ensures that the distribution of characteristics in a number of generations, which contributes to the survival of individual members of species. At a time when M. was completing his first scientific paper, . virtually nothing was known about the actual mechanism of inheritance, . a common method for studying the evolution and heredity was, . to, . studying the morphology and physiology (the physical form and function) of representatives of different species, . try to draw a conclusion about the causes of their similarities or differences,
. An important part of that research was to study embryonic development.
In accordance with this practice, M. also began to study the morphology and physiology, when I entered in 1887, Mr.. at Johns Hopkins University. Three years later he received his Ph.D. for research on the embryology of sea spiders. In 1891, Mr.. he became an associate professor of biology at Bryn Mayrovskom college, being by this time perfectly familiar with comparative and descriptive methods. However, like Darwin's theory, these methods did not give any explanation of the hereditary transmission of traits. Therefore M. turned to experimental methods, hoping that accurate and verifiable results of experiments in the end will answer the right questions. In 1897, . The ability of some animals to recover the lost body parts - the devil, . apparently closely related to the successful survival of the individual, . - He published the first of its series of articles on this topic, . which continued to develop throughout life,
. In its 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 made in the walls of this institution, were still devoted to experimental embryology.
Interest in M. to an emerging scientific discipline - genetics - was caused by the fact that in 1900. attention of the scientific world was once again focused on the work of Gregor Mendel on inheritance of traits in peas, which he published in 1886. Mendel showed that the signs are inherited according to strict mathematical laws, revealed a separate entity independent of each attribute. In 1902, Mr.. American biologist William C. Sutton suggested that the hypothetical 'factors' Mendel - units of heredity, now known as genes - are located inside or on the surface structures of the cell nucleus called chromosomes. Were needed, however, direct confirmation of the chromosome theory of heredity. M. skeptical of the above-mentioned theory, assuming that the chromosomes are not the bearers of heredity, but are the products of early stages of development. He was skeptical and to Darwin's idea of "gradual change ', preferring to it the theory of the Dutch botanist Hugo de Vries, who believed that the new species is formed as a result of mutations.
In 1908, Mr.. M. genetichekoe started studying the fruit fly Drosophila melanogaster, . small insects, . perfectly suited for genetic studies: the flies were only 4 of chromosome, . she began to proliferate after 2 weeks after birth, . and it was easy to learn for life, . duration of which was 3 months,
. Took to grow and explore millions of fruit flies, before M. and his colleagues at Columbia University came to the conclusion that chromosomes are indeed directly linked to heredity.
The results held some M. experiments on breeding fruit fly, . seemed, . contrary to Mendel's laws of independent inheritance, . that every organism has genes, . controlling a particular trait, . and inheritance of a trait, . which is the, . example, . sex animal, . not depend on the succession of another - for example, . eye color,
. A group led by Moscow, has found that some signs, obviously, still linked. In other words, their combination is found in the offspring more often than expected by statistical laws of Mendel. For example, Beloglazov - mutant trait - almost always seen only in males. M. called this phenomenon contact with the floor. Tendency to adhesion prompted Moscow that the genes apparently are in close proximity to each other on the same chromosome. Were found, four are linked groups of genes in fruit flies, which are consistent with its four pairs of chromosomes.
In early 1912. to a group of researchers working together with M. in 'mushin room', joined by two students at Columbia University - Alfred X. Stertevan and Calvin B. Bridges. Two years later their example was followed by graduate Herman J. Moeller. Surprisingly, M. and his colleagues pointed out that genes located on the same chromosome, inherited together less often than might be expected. In most cells had two chromosomes of each type, and M. suspected that the chromosomes in the pair may be split and recombine, thereby allowing to exchange genes. This idea was confirmed by data obtained under the microscope of intertwined chromosomes, which, according to the first observed them in 1909. Belgian scholar FA. Janssens, can share among themselves their own sites.
The greater the distance between two genes in one chromosome, M. reasoned, the greater the likelihood the gap. If so, then the genes will be inherited together. Conversely, genes located on chromosome close to each other, are less likely to be separated. Already in 1911. Stertevan realized that the degree of adhesion of the two genes in the chromosome can serve as the value of the linear distance between them. Based on this principle, M. colleagues were 'map', showing the relative positions of genes in the chromosomes of the fruit fly. The idea that genes are located in the chromosome in a specific linear sequence, and, further, that the basis of adhesion of the proximity of two genes on the chromosome, can be attributed to the major achievements of the genetic theory. In 1915, Mr.. M., . Bridges, . Stertevan and Muller reported on their studies in the book 'The Mechanism of Mendelian inheritance' ( 'The Mechanism Heredity'), . showing, . that heredity has a well-defined laws and can be described in precise quantitative methods.,
. In 1928, Mr.
. M. resigned from Columbia College, to help organize the biology department at the California Institute of Technology (Caltech) in Pasadena. Together with him in the new agency took over some of his former students and staff, which allowed him to collect an outstanding team of researchers. The work performed by the group M. and other specialists in Pasadena, won deserved fame leading institution in the field of experimental biology, which has been preserved for him, and after the M. changed the theme of research, taking up mainly embryology.
M. received the Nobel Prize in Physiology or Medicine 1933. 'for discoveries concerning the role of chromosomes in heredity'. In his Nobel lecture M. stated that the contribution of genetics in medicine is mainly a purely educational nature. 'In the past, the very subject of human heredity was so vague and littered with all sorts of myths and prejudices that the acquisition of scientific understanding of the subject is already achieving the primary value', - he said. In continuation of speech M. suggested that the discovery of the phenomenon of adhesion to the floor may someday prove useful for the diagnosis of genetic diseases.
After receiving the Nobel Prize M. continued to carry out administrative work at Caltech, . combining it with research on a variety of topics, . as biological regeneration, . laws of inheritance in pigeons, . secondary sexual characteristics in salamanders and cross the line in the inheritance of rare species of mice.,
. Reputed stingy when it came to the institute funds, M
. life was a very generous person and often secretly funded school gifted students.
In 1904. M. married Lilian Vaughan Sampson, cytology, his former student at Bryn-Maire, the couple had four children. In 1941, Mr.. M. received the title of honorary professor of biology at Caltech. Four years later, he died in Pasadena on gastric bleeding.
Among the many awards M. - Darwin Medal (1924) and the Copley Medal of Royal Society of London (1939). He was elected a member of the Royal Society of London, the National Academy of Sciences, the American Association for the Development of Science, the American Philosophical Society, the Genetics Society of America and the American Society of Naturalists.