Joshua Lederberg (1925 - 2008)
May 23, 1925, Montclair, N.J., U.S.—died Feb. 2, 2008, New York, N.Y.)
American geneticist, pioneer in the field of bacterial genetics, who
shared the 1958 Nobel Prize for Physiology or Medicine (with George W. Beadle
and Edward L. Tatum
) for discovering the mechanisms of genetic recombination in bacteria.
studied under Tatum at Yale (Ph.D., 1948) and taught at the University
of Wisconsin (1947–59), where he established a department of medical
genetics. In 1959 he joined the faculty of the Stanford Medical School,
serving as director of the Kennedy Laboratories of Molecular Medicine
there from 1962 to 1978, when he moved to New York City to become
president of Rockefeller University. He held that post until 1990.
With Tatum he published “Gene Recombination in Escherichia coli”
(1946), in which he reported that the mixing of two different strains
of a bacterium resulted in genetic recombination between them and thus
to a new, crossbred strain of the bacterium. Scientists had previously
thought that bacteria only reproduced asexually—i.e., by cells
splitting in two; Lederberg and Tatum showed that they could also
reproduce sexually, and that bacterial genetic systems are similar to
those of multicellular organisms.
While biologists who had not previously believed that “sex” existed in bacteria such as E. coli
were still confirming Lederberg"s discovery, he and his student Norton
D. Zinder reported another and equally surprising finding. In the paper
“Genetic Exchange in Salmonella” (1952), they
revealed that certain bacteriophages (bacteria-infecting viruses) were
capable of carrying a bacterial gene from one bacterium to another, a
phenomenon they termed transduction.
discoveries greatly increased the utility of bacteria as a tool in
genetics research, and it soon became as important as the fruit fly Drosophila and the bread mold Neurospora.
Moreover, his discovery of transduction provided the first hint that
genes could be inserted into cells. The realization that the genetic
material of living things could be directly manipulated eventually bore
fruit in the field of genetic engineering, or recombinant DNA