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Lederberg, Joshua

( The American geneticist, Nobel Prize in Physiology or Medicine, 1958)

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Biography Lederberg, Joshua
genus. May 23, 1925
American geneticist Joshua Lederberg was born in MONTCLAR (New Jersey), the son of Rabbi Zvi Hirsch Lederberg and Esther Lederberg (Goldenbaum). The two years before the birth of Joshua, his parents emigrated to America from Palestine. L. received his primary education in public schools in New York. In 1941, Mr.. He graduated from high school. After school, L. studied zoology at the initial medical course at Columbia University and at the age of 19 years of age received a bachelor's degree with honors. He then went to medical school at the College of Physicians and Surgeons of Columbia University, but continued research work under the direction of F. Ryan at the Department of Zoology at Columbia University.
After two years of medical school A. summer 1944. worked at Yale University as a senior laboratory Department of Microbiology. Although L. was going to fall back to medical school, he stayed at Yale University and continued his research work and study in order to obtain a doctorate in microbiology, led by microbiologist and biochemist Edward L. Teytema.
At Stanford University, Tate and his colleague, George Y. Beadle conducted studies, . opened up new avenues of Biochemical Genetics - Section of Genetics, . studying the biochemical processes, . resulting in the genotype of an organism (the set of all its genes) is implemented in its phenotype (a set of physical characteristics),
. Genetics was born in 1866, when a Dominican monk Gregor Mendel suggested that the inheritance of physical characteristics meet certain 'elements', which are now called genes.
At the beginning of XX century. Mendel's work, has not received recognition during his lifetime, became the basis for new research. The researchers found that genes are located in the intranuclear formations - chromosomes. However, only in 1940. it became known that the genes are formed by deoxyribonucleic acid (DNA). Hermann Muller in studies conducted in the 20's. Proved that X-rays cause genetic mutations, and in the early 40-ies. Beadle and Tate were able to cause mutations in fungi. However, they found that genes, ie. part of the DNA molecule, which govern the formation of cellular enzymes (proteins required for various biochemical reactions in the body) and thus regulate the biochemical processes in cells.
At a time when L. under Teytema began to explore the genetics of bacteria, scientists thought that these organisms reproduce asexually: one bacterium divides and gives rise to two other. However L. thanks to the work Teytema and Beadle and his own research at Columbia University, knew that the fungi reproduce sexually by means of temporary associations (conjugation) of two individual cells with the formation of the third - a subsidiary. L. suggested that the bacteria must also reproduce sexually. To test this assumption, he, together with Teytemom studied species in the colon of human and animal E. coli (Escherichia coli). Found that the bacteria can reproduce sexually by conjugation of two separate cells. It is formed daughter cells, which is divided, and its progeny is also undergoing successive divisions, resulting in a new generation of bacteria. Crossed two strains of E. coli, L. and Tate found that the offspring inherit some traits of both parental strains. They named this phenomenon of sexual genetic recombination. When genetic recombination of bacterial cells from one cell to another to transmit the complete extra set of chromosomes and their genes.
In 1947, Mr.. L. retired from Yale University and became a professor of genetics at the University of Wisconsin. Here he continued to explore the genetic recombination of bacteria. The following year he received his doctorate in microbiology from Yale University. At the University of Wisconsin A. developed a special technique of using ultraviolet rays or other factors causing mutations isolated mutants of a bacterial species. He proved that mutations occur spontaneously, and thus confirmed the previously existing hypothesis in evolutionary genetics. Applying a method for breeding bacteria resistant to penicillin and streptomycin, he received the bacteria resistant to both antibiotics. In addition, he proved that by using such methods can be relatively non-virulent bacteria, and vice versa.
In collaboration with the University of Wisconsin graduate student Norton Zinder L. found in bacteria, the process of transduction. In transduction, or transfer of fragments of chromosomes from one cell to another, changing the genetic code of the recipient cells. Some scientists believe that viruses can alter the genetic code of bacteria through a similar process. Since the definition of the order of genes in the chromosomes is based on methods related to transduction, the work of L. made a significant contribution to further research and discoveries in the field of bacterial genetics. In addition, it opened the way for development of modern recombinant genetics - the study of the processes by which you can change the genetic code of bacteria to develop certain biochemical substances.
In 1957. L. was asked to organize and lead the department of genetics at the University of Wisconsin. Before you begin any new responsibilities, it is thanks to scholarships, established by the Fulbright Foundation, was able to conduct research in the University of Melbourne in Australia.
In 1958, Mr.. L. was awarded the Nobel Prize in Physiology or Medicine "for discoveries concerning genetic recombination and the organization of genetic material in bacteria '. The second half of the prize was awarded to George Beadle and Tate 'for their discoveries concerning the role of genes in specific biochemical processes'.
In the same year, L. was promoted to professor and head of the department of genetics at Stanford University. In 1962. He became the director of the Laboratory of Molecular Medicine, Joseph Kennedy Jr. in the same university.
In the early development of the American space program L. expressed different views on scientific and medical implications of space exploration and was appointed consultant to the program 'Viking', the essence of which was to develop a project space flight to Mars. In addition, he was an adviser to the World Health Organization on the possible implications of biological warfare and biological weapons.
In 1978. L. resigned from Stanford University and became the rector of the Rockefeller University. In addition to work on genetics, he has written many books on the biological sciences and the future of the human species.
In 1946, Mr.. L. married a former graduate student Teytema Esther Zimmer. After their divorce in 1968, he. married Margaret Stein Kirsch, in the family they had a son and a daughter.
In addition to the Nobel Prize, A. awarded the Eli Lilly Award of the Society of American Bacteriologists (1953) and medals of Alexander Hamilton, Columbia University. He has honorary degrees from Yale, Columbia, New York and University of Turin. He is a member of the National Academy of Sciences of the USA, the American Chemical Society and American Society of Geneticists. In 1979. He was elected a foreign member of the London Royal Scientific Society.

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Lederberg, Joshua, photo, biography
Lederberg, Joshua, photo, biography Lederberg, Joshua  The American geneticist, Nobel Prize in Physiology or Medicine, 1958, photo, biography
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