News in brief: Fins to limbs with flip of genetic switch

Boost of gene activity may help explain how arms and legs evolved

By Tina Hesman Saey, 16:16 PM December 12, 2012

Evolving limbs from fins may be as easy as taking the activity of a few genes and kicking it up a notch, a new study suggests.

Many evolutionary biologists have thought that four-limbed creatures evolved from finned ancestors. Forming limbs involves turning on body patterning genes in two precisely timed phases, first in the back legs and then, later, in the part of the limb that will become the hand or foot. Fish have those genes but turn them on only once, or at very low levels during the...

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