Tatum, Edward Lawrie (1909-1975), was an American biochemist who helped demonstrate that genes regulate specific chemical processes For that work, he shared the 1958 Nobel Prize physiology or medicine with George Wells Beadle and Joshua Lederberg.

Tatum received a bachelor's degree in chemistry (1931), a master's degree in microbiology (1932), and a doctoral degree (1934) from the University of Wisconsin at Madison. He was a research associate at Stanford University from 1937 to 1941. While there, he worked with Beadle in researching the relationship between genes and biochemical reactions. Using X rays to cause mutations of the pink bread mold Neurospora crassa, they discovered that some of the mutants lost the ability to create an essential amino acid or vitamin. The mutated strains of the mold were then crossed with normal strains. The resulting offspring inherited the metabolic defect as a recessive trait, proving that the mutations were genetic defects. Ultimately, their research established that when genetic mutations affect a specific chemical reaction, the enzyme that catalyzes that reaction will be altered or missing. Thus, the “one gene-one enzyme” theory shows that each gene determines the structure of a specific enzyme.

From 1945 to 1948, Tatum was a professor at Yale University, where he conducted his mutation experiments on bacteria. With Lederberg, he discovered the occurrence of genetic recombination, or procreation, between Escherichia coli bacteria. Mainly because of this work, bacteria became the primary source of information regarding genetic control of biochemical processes.

He was a professor at the Rockefeller Institute of Medical Research (now Rockefeller University) in New York City from 1957 until his death in 1975. He was elected to the National Academy Sciences in 1952, and was a founding member the Annual Review of Genetics.