George Wells Beadle (Beadle George Wells)( The American geneticist, Nobel Prize in Physiology or Medicine, 1958)
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Biography George Wells Beadle (Beadle George Wells)
October 22, 1903, Mr.. - June 9, 1989
American geneticist George Wells Beadle was born in Wahoo (Nebraska). His parents were Chauncey Elmer Beadle Beadle and Hattie (Elbro). He was middle-age of three children in the family. When George was four years old, his mother died. After the death of the eldest son in an accident his father decided that George was in his time will be to manage family-owned farm in the area of 16 hectares. However, the young physics teacher from high school, George was able to arouse interest in science and to persuade him to go to college. In 1922, Mr.. B. enrolled in college п¦пЁя-п+п¦я¬п¦я-я-я¬я-я- University of Nebraska. During the second summer vacation, he studied the genetics of hybrid wheat at the department of agronomy.
In 1926, Mr.. B. received a bachelor of science degree, and the next year - a Master of Science. Then he began to study biology in graduate school at Cornell University. There he worked under the guidance R.A. Emerson, a renowned expert in plant genetics, who studied, in particular, Barbara McClintock, a future Nobel Prize. Emerson took the B. part-time assistant and instructed him to make a review on the genetics of maize. Therefore Thesis B. devoted meiosis (one way of dividing cells) in maize.
Chromosomes - carriers of genetic material in the nuclei of cells of plants and animals - are composed of genes. Genes are molecules of deoxyribonucleic acid (DNA), directing and regulating biochemical processes in cells. In the process of meiosis are formed germ, or sex cells (gametes) having a single set of chromosomes of asexual (somatic) cells. At fertilization newly formed pairs of chromosomes, and their number becomes normal. B. found that the inheritance of genetic defects in the pollen of maize is associated with violation of the splitting of chromosomes during meiosis.
In 1931, Mr.. B. received his doctorate in genetics from Cornell University and in the next two years he worked as a staff member of the National Council for Scientific Research at the Faculty of Biology, California Institute of Technology in Pasadena. Here, his head was Thomas Hunt Morgan, one of the leading geneticists, who studied the genetic processes in the fruit fly Drosophila (Drosophila melanogaster). B. studied the crossing over of chromosomes - a process that occurs during meiosis and leads to the exchange of genetic material between chromosomes. He found that crossing-over and recombination of genetic material during meiosis occur by chance.
In 1933 ... 1935. B. was a teacher of the Faculty of Biology, California Institute of Technology and worked with Boris Ephrussi, embryologist of the University of Paris, temporarily working in the department of Morgan. Researchers interested in the problem of inheritance of eye color in Drosophila, . in particular biochemical processes, . leading to the formation of a particular phenotype (physical characteristics of the organism, . such as eye color) on the basis of a genotype (the set of all genes of this individual),
. In 1935. B. Ephrussi worked in the laboratory at the Institute of Physical and Chemical Biology in Paris. Here, scientists found that the biochemical precursor of eye pigment (ie. substance from which the pigment is formed) in Drosophila serves as the amino acid tryptophan.
In 1936, Mr.. B. returned to the United States and became an assistant professor of genetics at Harvard University. The following year he was appointed professor of biology at Stanford University. At this time, biochemical genetics, who studied the biochemical processes that lead to the implementation of the genotype in the form of the phenotype, was in its infancy. Modern genetics appeared in 1856, when the Czech Dominican monk Gregor Mendel published his theory of the laws of heredity. Mendel believed that the inheritance of physical characteristics (eg, flower color) correspond to the special 'elements', which are now called genes. Mendel's experiments on plants have shown that some genes are dominant, and others - recessive. A dominant gene causes the development of a physical trait, even if it is contained in only one of two chromosomes, a recessive gene is shown only when it is available in both chromosomes. Article Mendel and his laws of heredity were forgotten for half a century, and only in the beginning of XX century, it again turned to the genetics of a new generation.
In studies conducted in the first third of XX century., It was found that the genes located on chromosomes. In 1902, Mr.. English physician and biochemist Archibald Garrod discovered that certain types of deficiency of enzymes (proteins needed for biochemical reactions in the body) from his patients are congenital. Works Garrod raised the question, not whether certain genes are responsible for managing the synthesis of specific enzymes. This question agitated and B. In 1926, Mr.. Hermann Muller, who worked with fruit flies, found that X-rays induced mutations in the genetic material of these flies, and that these mutations lead to defects in the structure and physical deformities.
In 1937, Mr.. to research B., who worked at Stanford University, joined Edward L. Tate, who studied microbiology and biochemistry at the University of Wisconsin. At this time, B. I was searching for his experiments more suitable object than the Drosophila. Even in graduate school at Cornell University and then at Caltech, he had heard of genetic studies conducted on Neurospora crassa - fungi, forming pinkish mold on bread. As these microorganisms grow and multiply rapidly, it was possible for a short time to investigate several generations. Genetic features of Neurospora have been partially studied by other scientists, and Tate, who studied feeding habits of this fungus in 1941. decided to proceed with the genetic experiments with them.
B. and Tate rightly assumed that the function of genes can be studied, damaging some of them. From the works of Muller was known that the X-ray irradiation of the genetic material mutation frequency increases about 100 times. Therefore B. and Tate began to grow colonies of Neurospora in a medium containing only some of the necessary food for this fungus substance, and then were exposed to X-rays. After such exposure alone colony bred normally, while others died, while others continued to grow, but they could not normally reproduce. B. and Tate investigated this latter group. They transplanted fungi from it in 1000 different environments and to each of them added a substance that normally developing fungi can synthesize their own. In a medium N299, to which was added vitamin B6, irradiated cultures began to grow normally, suggesting that irradiation caused a mutation of the gene responsible for the synthesis of the vitamin. In order to determine whether there is a genetic defect, B. and Tate crossed irradiated mushrooms with impaired synthesis of vitamin B6 with healthy. It turned out that this violation is transmitted by recessive type described by Mendel. Experiments have shown that certain genes are responsible for the synthesis of specific cellular substances. Laboratory techniques that B. and Tate developed at Stanford University, were useful for increasing the production of open-pharmacological Alexander Fleming's penicillin - a substance formed by fungi.
Until 1946. B. worked at Stanford University and then became a professor of biology and head of department, who previously headed Morgan, at the California Institute of Technology. In 1953, Mr.. B., . elected president of the American Association for the Advancement of Science, . urged the Government to review policy on privacy, . proposing to create a more open society, . requiring less secrecy of research scientists and admission to special information,
. Led by their association in 1955. adopted a decree according to which in the cities, where the segregation, scientific conferences should be conducted.
Half of the Nobel Prize in Physiology or Medicine for 1958. was awarded to B. and Tate 'for their discoveries concerning the role of genes in specific biochemical processes'. The second half was awarded to Joshua Lederberg for similar work in the field of genetics. In conclusion, Nobel lecture B. said: 'At first botanists and zoologists were indifferent and sometimes even hostile to the [genetics]. Often been said that [genetics] deals only with surface properties ... [But now] because of rapidly increasing knowledge about the structure of proteins and nucleic acids for the first time in the history of science the opportunity for geneticists, . biochemists and biophysicists to discuss the major problems of biology in the common language of molecular structures. ",
. In 1961
. B. resigned from the California Institute of Technology and became a professor of biology and the Rector of the University of Chicago. In 1968. He walked away from the administration and continued work on the genetics and evolution of maize. In 1970. He returned to California and became a trustee of California Institute of Technology. The following year he became an honorary trustee of the University of Chicago.
In 1928, Mr.. B. married Marion Cecil Hill. They have one son was born. In 1953, Mr.. couple divorced, and in the same year, B. married novelist Muriel McClure Burnet. From a previous marriage, she also had one son. Common children of B. and his second wife was. B. had the appearance of man, is constantly inspired by the ideas. He loved skiing, mountaineering and gardening. In addition, he loved Siamese cats.
In addition to the Nobel Prize, B. won many other awards, t.ch. Lasker Award of the American Public Health Association (1950), . Prize Fund Emile Christian Hansen for research in the field of microbiology, . awarded by the Danish Carlsberg Laboratory (1953), . Memorial Prize Yeshiva University's Albert Einstein (1958) and the Kimber Genetics Award of the National Academy of Sciences USA (1960),
. He was a member of many scientific societies in t.ch. American Society of Genetics (1946 g. - President), American Association for the Advancement of Science (from 1953. - President), the Royal Scientific Society and the Royal Danish Academy of Sciences. He worked in the Committee on Genetic changes due to atomic radiation in the National Academy of Sciences and the Advisory Committee on Biology and Medicine Atomic Energy Commission.