Edward B. Lewis

Lewis, Edward B. (1918-2004) was an American biologist who shared the 1995 Nobel Prize in physiology or medicine for his studies on genetics using fruit flies. He shared the prize with biologists Christiane Nusslein-Volhard of Germany and Eric Francis Wieschaus of the United States.

Lewis's work on fruit flies laid the foundation for what is now known about the genes that regulate the development of specific regions of the body. His work could help scientists learn which genes are responsible for about 40 percent of the congenital malformations that develop in people due to unknown reasons.


Lewis was born in Wilkes-Barre, Pennsylvania, May 20, 1918, to Laura (Histead) Lewis and Edward B. Lewis. He received a B.A. degree in biostatistics from the University of Minnesota in 1939 and an M.S. degree in meteorology and a Ph.D. degree in genetics from the California Institute of Technology (Caltech) in Pasadena in 1942. He reached the rank of captain in the U.S. Army's Air Force, serving from 1942 to 1945 as a meteorologist and oceanographer in the Pacific region.

Lewis joined the Caltech faculty in 1946 and spent his entire career there teaching biology. He began his research in the 1940's by breeding fruit flies and exposing them to radiation to cause mutations (genetic changes). He chose the fruit fly because it is a classic genetic specimen. They have a genetic structure similar to that of human beings but they also reproduce rapidly and develop from fertilized egg to embryo in only nine days. This allows scientists to observe many generations of fruit flies in short periods.

Lewis discovered that the genes that provided the code for the fly's body were segmented and ordered, even in the embryo stage. He saw how these genes dictated the development of each segment of the body. By causing mutations in certain genes, he found that he could cause flies to grow extra body parts or other abnormal features. Lewis published his findings in the science journal Nature in 1978 as a paper entitled “A Gene Complex Controlling Segmentation in Drosophila.” Drosophila melanogaster is the species scientists often use in heredity studies.

Lewis died in 2004, in Pasadena, California.