Tropical fruit flies taking over!

Scientists have been studying fruit fly genetics for a century. When they began to examine the genes found in whole populations of wild flies, they noticed a curious pattern.

Certain chromosomal markers (inversions) were common in populations living in warmer climates near the equator, and others were common in more polar, cool-weather populations.

It wasn’t clear what the genes associated with these different markers did exactly, but they seemed to help the flies cope with their divergent climates.

Now, scientists have gone back to many of the fly populations first studied — and have found that as the global climate has warmed, the warm-weather genetic markers are becoming more and more common.

Of the 22 fly populations on three continents that experienced warming trends, 21 seem to have already evolved in response to the climactic shift.

Berkeley University: Understanding Evolution, Jul 2008