The feathers, fur, and scales that adorn different members of the animal kingdom may look quite different, but they're all made of the same basic stuff. And, as it turns out, it only takes a relatively simple genetic tweak to produce one instead of the other.
By targeting the sonic hedgehog (Shh) gene, geneticists Michel Milinkovitch and Rory Cooper of the University of Geneva in Switzerland altered embryonic chickens to grow feathers instead of scales on their usually squamous feet.
And the alteration is permanent. Once hatched, the chicken's unusually feathery feet will stay that way for life.
"We demonstrate that stage-specific transient agonism of sonic hedgehog (Shh) pathway signaling in chicken triggers a complete and permanent transition from reticulate scales to feathers on the ventral surfaces of the foot and digits," the researchers write.
