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.
natural selection
Darwin’s short-beak enigma solved
Sex, lice and videotape
Biologists drove the divergence of different-sized feather lice from a single population. In four years the evolved lice had trouble mating with each other, a sign of speciation and they caught it on tape.