Gene controls beak morphology

Scientists have pinpointed a molecular basis for size variations in the beaks of Galapagos finches', a phenomenon observed by Charles Darwin more than a century and a half ago.

In this week's issue of Science, Harvard University developmental biologist Cliff Tabin and colleagues identified bone morphogenetic protein (Bmp)-4 as a key player in the pathway controlling avian beak development. His team includes Peter and Rosemary Grant, whose research endeavors on the islands were recorded in Jonathan Weiner's Pulitzer Prize-winning account.

"The idea is that these finches have evolved a mechanism for changing their jaw skeleton rapidly and in response to environmental pressures," explained cell biologist and orthopedic surgeon Jill Helms, who recently moved from the University of California, San Francisco, to Stanford University.

Helms, who was not involved in the study, said that Tabin's group tried to answer a question about beak variations first posed by Darwin himself. "He said ...