But now, thanks to the colorful derriere of a wild fruit fly, captured on a compost heap by a University of Wisconsin-Madison post-doctoral student, scientists have been able to document a rare example of molecular convergence, the process by which different animals use the same genes to repeatedly invent similar body patterns and structures.

Writing in the current issue (Aug. 21) of the journal Nature, a group led by Sean Carroll and Nicolas Gompel of the Howard Hughes Medical Institute (HHMI) at UW-Madison, describes the genetic mechanisms that control the colors and patterns on fruit fly abdomens. The study suggests that the simple modulation of a transcription factor, a protein that can bind to DNA and influence its activity, may be responsible for governing the diversity of body color patterns among related animal species.

"At the visual level, evolution repeats itself," Carroll explains. "Insects evolved wings. Birds evolved wings. Bats evolved wings. The question we are asking is - in related animals like insects, for example - did they arrive at these body plans or decorations in the same way?"

Conveniently, the answer was found with the help of a wild fruit fly, captured by Gompel, a post-doctoral fellow. Pursuing his hobby of collecting and systematizing insects near a wooded tract close to Eagle Heights, a housing complex for UW-Madison students and their families, Gompel captured a wild fruit fly that looked very much like the species Drosophila melanogaster, the workhorse of many modern genetics laboratories.

"I found a Drosophila with a pattern of pigmentation similar to melanogaster, though this species was obviously very distant," Gompel explains. "I bred it and studied it, and found that the genetics underlying its pigment pattern was similar to melanogaster."
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Contact: Nicolas Gompel
ngompel@wisc.edu
608-262-7898
University of Wisconsin-Madison
20-Aug-2003