Feathered-foot pigeons grow wing genes in their legs
Some fancy pigeons sprout feathers on their feet because a gene that normally builds wings switches on in the legs, while a leg-building gene quiets down. The quirk lies in DNA switches rather than the genes themselves, and scientists now use these birds to study how dinosaurs may have traded feathered feet for scaly ones.
Pigeons were among the first birds people tamed. Cuneiform tablets from Mesopotamia and Egyptian hieroglyphs mention them more than 5,000 years ago, and some researchers push domestication back as far as 10,000 years. Genetically, today's breeds sit closest to rock doves from the region spanning Syria, Jordan, Iraq and Arabia. Their delicate bones leave a poor fossil trail, so the details remain murky.
Heavy interbreeding with feral and domestic birds has made pure wild rock doves rare, pushed to remote coasts such as Scotland's Outer Hebrides. Carved dovecotes survive in the rocks of Cappadocia's Pigeon Valley, the Mughal emperor Akbar travelled with thousands of the birds, and European settlers carried them to North America, possibly first to Nova Scotia in 1606. From the 18th century European fanciers mixed imported stock into ever stranger breeds; Charles Darwin was one of them, and his hobby fed a book on variation under domestication.
More than 350 breeds now exist. Colour follows the sex chromosomes: males carry colour genes from both parents, but females inherit colour only from their father, so two chicks from one clutch can look quite different. A single recessive gene gives some birds a crest of feathers pointing forward, and pouter breeds can puff their crops into a round globe of air.
Breeding habits stay close to the wild bird. A pair builds a flimsy stick nest, and the two eggs hatch after 17 to 19 days. Both parents feed the squabs a rich crop milk and guard the nest fiercely, even against their keepers. The young reach adult size at around four weeks, and a hen may start a fresh clutch while her mate finishes rearing the last.
Source: Domestic pigeon
