Dr. Perri said that among ancient American dogs, which disappeared, leaving only traces of their genetics in a few modern breeds, “there are two main groups which share a common ancestor about 23,000 years ago.”
On the human side there is a similar split.
The names get a bit hard to keep track of, but one group called the Ancient North Siberians mixed with another group from which Ancestral Native Americans split about 21,000 years ago. The hypothesis suggests that in addition to providing some genes, the ancient North Siberians also gave dogs to people, some of whom eventually migrated to North America, taking the dogs with them. As Dr. Meltzer said, “Dogs are not going to go to the new world without people.”
But the several different groups in Siberia appear to have been isolated from outside contact from about 30,000 years ago to 15,000 years ago. So, Dr. Perri said, if there is “this isolated population who had no interaction with anyone outside of Siberia after 30,000 years ago, who gave the dogs to the ancestors of Native Americans?”
The data suggest that it was the ancient North Siberians, who, having been isolated for thousands of years, must have been the people who first domesticated wolves, or with whom wolves domesticated themselves, feeding on leftovers or discards from the hunt.
Dr. Meltzer said these Siberians lived in small groups of 25 or so in a vast, open landscape. Ancient DNA evidence shows that they married outside of their small groups, and so had to seek one another out. “People are exchanging information, they’re exchanging mates, they’re maybe exchanging their wolf pups,” he said.
Pontus Skoglund, an ancient DNA expert who studies the origin of dogs at the Crick Institute in London and was not involved in the research, said, “Siberia could very well be the origin of dogs. Absolutely.” But, he said this was one possibility only. He said the analysis in the paper depended largely on mitochondrial DNA, which traces only the maternal line and is therefore incomplete.
“It’s still an open question for me,” he said. “It could be many other corners of Eurasia as well.”
New information on ancient DNA recovered from Siberian dog fossils that are 18,000 or more years old could help prove or disprove the hypothesis, Dr. Perri said, and she and her colleagues are working on those studies now.