The Curious Case of Pigeon Beaks

Charles Darwin was obsessed with domestic pigeons. He thought they held the secrets of selection in their beaks. Free from the bonds of natural selection, the 350-plus breeds of domestic pigeons have beaks of all shapes and sizes within a single species (Columba livia). The most striking are beaks so short that they sometimes prevent parents from feeding their own young. Centuries of interbreeding taught early pigeon fanciers that beak length was likely regulated by just a few heritable factors. Yet modern geneticists have failed to solve Darwin’s mystery by pinpointing the molecular machinery controlling short beaks—until now.

In a new study, a team of University of Utah biologists led by Elena Boer and Michael Shapiro discovered that a mutation in the ROR2 gene is linked to beak size reduction in numerous breeds of domestic pigeons. Surprisingly, mutations in ROR2 also underlie a human disorder called Robinow syndrome.