This implies that all modern dogs, as well as the Newgrange canine, can trace their ancestry back to Asia.īut here's the twist: Archaeologists previously had found the remains of dogs in Germany that may be more than 16,000 years old, suggesting that dogs had already been domesticated in Europe by the time the Asian canines got there. Taken together, the data suggest that humans domesticated dogs in Asia more than 14,000 years ago, and that a small subset of these animals eventually migrated west through Eurasia, probably with people. (A similar pattern is seen with the original human migration out of Africa.) The analysis also revealed a "genetic bottleneck" in Western dogs-a reduction in genetic diversity typically tied to a sharp decline in a population's numbers, as can occur when a small band of individuals splits off from the main group. This rate suggests that the East-West split happened sometime between 6400 and 14,000 years ago. Researchers used it, in conjunction with the complete genomes of several modern dogs and wolves, to calculate a genetic mutation rate for canines. To figure out when this divide occurred, the Newgrange specimen was critical. "We never saw this split before because we didn't have enough samples." "I was like, 'Holy shit!'" says project leader Greger Larson, an evolutionary biologist at Oxford. The team then created a family tree for the animals, which revealed a deep divide between European dogs (like the Newgrange canine and the golden retriever) and Asian dogs (like the shar pei and free-ranging village dogs from Tibet and Vietnam). Researchers led by Laurent Frantz, an evolutionary geneticist at the University of Oxford in the United Kingdom, sequenced this specimen's entire nuclear genome-the first complete genome from an ancient dog to be published-and compared it to the nuclear DNA of 605 modern dogs from around the world. The study includes a unique specimen: the inner ear bone of a nearly 5000-year-old dog unearthed from Newgrange, a football field–sized mound of dirt and stone on the east coast of Ireland, built around the time of Stonehenge. Robert Wayne, an evolutionary biologist at the University of California, Los Angeles, whose work has shown that dogs arose in Europe, says the results-although plausible-are too preliminary to settle the question. "These are fantastic data that are going to be extremely valuable for the field," says Peter Savolainen, a geneticist at the Royal Institute of Technology in Stockholm and the leading proponent of Asian dog origins. The findings could resolve a rift that has roiled the canine origins community-but the case isn't This week in Science, researchers report that genetic analysis of hundreds of canines reveals that dogs may have been domesticated twice, once in Asia and once in Europe or the Near East, although European ancestry has mostly vanished from today's dogs. Did wolves first forge their special relationship with humans in Europe, or in Asia? The answer, according to a new study, is yes. For years, scientists have debated where dogs came from.
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