(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."
A side 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 Nüsslein-Volhard of the Max Planck Institute
for Developmental Biology in Tübingen, 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."
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