1918-2004, American geneticist, b. Wilkes-Barre, Pa., grad. California Institute of Technology (Ph.D. 1942). After serving as a meteorologist with the U.S. Army Air Corps during World War II, he returned to the California Institute of Technology and taught there until he retired in 1988. In studying a four-winged mutant fruit fly, he identified the genes regulate the development of the fly's body segments and discovered that the arrangment of the genes in the DNA strand mimicked the arrangement of the body segments, a condition that is now known as the colinearity principle. For this work he shared the 1995 Nobel Prize in Physiology or Medicine with Eric F. Wieschaus and Christiane Nüsslein-Volhard. In the 1950s Lewis also investigated the effects of radiation and showed that exposure to low doses of X rays and other radiation sources involves greater risk than had been believed.
