Thursday, November 17, 2016

The Origins of Dogs

“Ten or 20 years ago, we looked at modern dogs and modern wolves, and that’s it,” says German geneticist Olaf Thalmann, currently at Poland’s Poznan University of Medical Sciences. “We have realized this is wrong. Now we’re going back to the cradle of domestication to look for answers there [because] the wolves we see today are not what gave rise to dogs.”

DNA in this ancient Irish dog’s temporal bone is distinct from modern dogs and wolves. It’s evidence that dogs had multiple origins.

In June, Science published a paper that heralds the new direction of research. According to the study, dogs were domesticated not once but twice, on opposite ends of the Eurasian continent at least 15,000 years ago. Previous studies assumed that domestication was a difficult and thus rare event, occurring only once. But the new dual-origin theory found that an ancient European population was replaced by an eastern Asian population as the latter expanded across the continent. Every dog alive today is descended from ancient Asian roots.

In addition to collecting DNA from hundreds of modern wolves as well as mutts and purebred dogs, the dual-origin researchers extracted DNA from dozens of ancient dogs, including a particularly high-value sample from a 4,800-year-old animal unearthed in Newgrange, Ireland.

“The ancient [Newgrange] dog had ancestry not found in modern dogs or in modern wolves,” says Mietje Germonpré, who was not part of the dual-origin team. The Belgian paleontologist has studied the remains of other older canids in Eurasia and believes some of them were early dogs — a controversial theory, but one this new research suggests may be correct.

“It’s the first hint toward what’s out there,” says Thalmann, who also wasn’t involved in the research. “It’s a wake-up call. The theory about multiple origins and timing was out there for some time, but this is the first evidence for it genetically.”

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