US biochemist who, in collaboration with George Wells Beadle (1903–89), produced convincing evidence that a single gene codes for a single specific enzyme. For this work, they were awarded the 1958 Nobel Prize for Physiology or Medicine.
Tatum was educated at the University of Wisconsin, receiving his PhD in microbiology in 1934. In 1937 he was appointed research associate at Stanford University and in 1940 began his work with Beadle. They irradiated conidia (spores) of the bread moulds Neurospora crassa and N. sitophila and allowed them to germinate on various culture media. In this way they discovered three mutant strains that had lost the ability to synthesize specific vitamins, implying that in each case the necessary enzyme was missing or nonfunctional. In subsequent crosses with normal strains, the mutant characters were shown to differ from normal by only a single gene. This gave considerable weight to the theory, now widely accepted, that one gene codes for one enzyme. Tatum then applied his technique to the bacterium Escherichia coli and found similar nutritionally deficient mutants. This led to his discovery, with Joshua Lederberg, of the phenomenon of genetic recombination, in which part of the bacterial chromosome is transferred from ‘male’ cells to ‘female’ cells by a form of sexual reproduction called conjugation. This represented a major step in the development of microbial genetics and the use of E. coli in recombinant DNA technology.
Tatum moved to Yale in 1945, becoming professor of microbiology, but returned to Stanford after three years. In 1957 he joined the Rockefeller Institute for Medical Research in New York.
Subjects: Science and Mathematics — Contemporary History (Post 1945).