viernes, 11 de noviembre de 2016

How farming changed the dog


Africa Studio/Shutterstock

Farming didn’t just revolutionize human society—it transformed the genome of our oldest friend, the dog. A new study reveals that by 7000 years ago, our canine companions were eating so much wheat and millet they made extra copies of starch-digesting genes to help them cope. And this adaptation is what allowed them to stay by our sides, even as our world changed.

The genetic evolution in dogs parallels what others have found in humans, says Peter Savolainen, an evolutionary geneticist at the Royal Institute of Technology in Stockholm, who was not involved with the work. "With farming we started to eat starch, and both we and dogs had to adapt to this change."

Some of the first insights into how farming changed the canine genome came 3 years ago. That’s when evolutionary geneticist Erik Axelsson of Uppsala University in Sweden and his colleagues discovered that dogs have four to 30 copies of a gene—Amy2B—that helps digest starch, whereas wolves typically only have two. Morgane Ollivier wanted to know just when that genetic change happened. A paleogeneticist at Ecole Normale Supéieure de Lyon in France, she teamed up with Axelsson and others, who extracted ancient DNA from the bones and teeth of 13 wolf and dog specimens collected from archaeological sites throughout Eurasia. Four of the ancient dogs—from a 7000-year-old site in Romania and 5000-year-old sites in Turkmenistan and France—had more than eight copies of Amy2B, Ollivier and her colleagues report today in Royal Society Open Science. They do not yet know how many copies ancient wolves had. [...] Science | AAAS