A change in a single gene ruffles the feathers of all pigeons with collars and crests, a new study shows.
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Many breeds of rock pigeons have these crests, even though they come from different branches of the pigeon family tree. So it was a surprise that all the birds owe their fancy plumage to the same mutation in a gene called EphB2, Michael Shapiro of the University of Utah and colleagues report online January 31 in Science. The researchers found that the mutation arose once and spread to many different types of pigeons through breeding programs. They don’t yet know whether the mutation arose in a wild ancestor of domesticated pigeons or if it sprang up only after domestication.
As different species evolve, some traits show up again and again. Scientists debate whether each occurrence comes from the same genetic mechanism, as in the pigeons, or from different mutations with the same result, says James Hanken, an evolutionary biologist at Harvard University.