Lewis, Edward B: (1918-2004) American geneticist and Nobel Laureate who showed how genes control embryonic development. In 1957 Lewis discovered that genes were arranged on chromosomes in the same order as they were activated along the body axis during development, a concept known as the colinearity principle. Lewis identified genes as switches that are turned on or off during development. As another scientist put it, "What Ed was able to do, in the absence of molecular understanding, was to come up with a basic concept of how genes work . . . in terms of a logical relationship, like a diagram of an electronic circuit."
Aside from pioneering work on embryonic development, Lewis did key work on the effects of radiation in an era when many thought that there was a threshold below which radiation could not cause cancer. Lewis analyzed data on Japanese A-bomb survivors and wrote in 1957 that "these data provide no evidence for a threshold dose for the induction of leukemia." Lewis also compared the leukemia incidence among radiologists to that among other physicians, finding that "chronic irradiation at a relatively low dose rate...appears to induce leukemia in radiologists at a rate...comparable to that observed for the Japanese survivors." Lewis was publically attacked by the Atomic Energy Commission and other scientists at the time but now it is clear he was entirely correct.
Lewis shared the 1995 Nobel Prize in Physiology or Medicine with Eric F. Wieschaus of Princeton University and Christiane Nusslein-Volhard of the Max Planck Institute for Developmental Biology in Tubingen, Germany. The Nobel Committee's presentation speech noted that: "The genes that Edward Lewis discovered have in fact the same order in our DNA as in that of the fruit fly, and they work in the same way. The knowledge gained about the development of the fruit fly has thus been a prerequisite for the recent advances in understanding how vertebrates develop." As a colleague at Caltech said of Ed Lewis, "He had a long-term obsession to come up with profound universal truths, which he did."