Edward B. Lewis

Edward B. Lewis (1918-2004), American geneticist and Nobel laureate. For his pioneering work with fruit-fly genetics, Lewis was awarded the 1995 Nobel Prize in physiology or medicine, which he shared with German geneticist Christiane Nüsslein-Volhard and American geneticist Eric F. Wieschaus.

Lewis was born in Wilkes-Barre, Pennsylvania, and became interested in genetics as a high school student when he read about mutations (genetic changes) in the common fruit fly. He received a B.S. degree in biostatistics from the University of Minnesota in 1939, followed by a Ph.D. degree in genetics in 1942 and an M.S. degree in meteorology in 1943, both from the California Institute of Technology (Caltech). In 1946 Lewis became a faculty member at Caltech, where he remained until his retirement in 1988.

Lewis devoted his entire academic career to the study of the fruit fly's genetic makeup. By studying mutations in the fruit fly and identifying which genes caused the mutations, he made two far-reaching discoveries about genes. The first was that a particular group of genes, called homeotic genes, controls the development of all the regions of the fly's body. These genes direct each cell to its proper location along the developing embryo's (see Embryology) body. His second discovery was the principal of colinearity, or the linear sequence of the homeotic genes. He found that the homeotic genes are arranged on the chromosome in a linear order that exactly corresponds to the order of the body regions that each gene controls. This finding, which was subsequently found to hold true for other animals as well, won him the Nobel Prize.