Edward Lawrie Tatum (December 14, 1909 – November 5, 1975) was an American geneticist. He shared half of the Nobel Prize in Physiology or Medicine in 1958 with George Beadle for showing that genes control individual steps in metabolism. The other half of that year's award went to Joshua Lederberg. Tatum went on to study genetics in bacteria. An active area of research in his laboratory was to understand the basis of Tryptophan biosynthesis in Escherichia coli. Later, Tatum and his student Joshua Lederberg showed that E. coli could share genetic information through recombination.