The ancestors of modern wolves and dogs split into different evolutionary lineages 27,000 to 40,000 years ago, much earlier than some other research has suggested, scientists reported Thursday.
The new finding is based on a bone fragment found on the Taimyr Peninsula in Siberia several years ago. When scientists studied the bone and reconstructed its genome—the first time that had been done for an ancient wolf, or any kind of ancient carnivore—they found it was a new species that lived 35,000 years ago.
Based on the differences between the genome of the new species, called the Taimyr wolf, and the genomes of modern wolves and dogs, the researchers built a family tree that shows wolves and dogs splitting much earlier than the 11,000 to 16,000 years ago that a study in 2014 concluded.
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Their study also gives some dog-park bragging rights to owners of Siberian huskies and Greenland sled dogs, which have inherited a portion of their genes from the Taimyr wolf.
The history of dogs is still murky, however, because it seems that different kinds of wolves and dogs have interbred at different times in different places over the past tens of thousands of years.Love Dalen, of the Swedish Museum of Natural History and an author of the report in Current Biology, said that the simplest explanation for the new evidence "is that dogs were domesticated as much as 30,000 years ago."
But, he said, the researchers' work does not prove that this is what happened. Pontus Skoglund, a research fellow at Harvard University and the first author of the research paper, said, "We can't just look at the DNA and say whether a canid was living with modern humans."
Laurent Frantz, a researcher at Oxford who also studies canine evolution, said that he thought the work was "a great milestone in studying wolf populations," although he said the timing of the domestication of dogs remained unclear.
The bone fragment was found by Dr. Dalen a few years ago when he was collecting fossils of ancient mammals on the Taimyr Peninsula. He said that for one unidentifiable fragment, he wrote in his field notebook, "Reindeer?"
But genetic tests showed that that fragment belonged to a wolf, and subsequent carbon dating put it around 35,000 years old. At that point, Dr. Dalen said, Dr. Skoglund suggested sequencing the genome.
As to the impact of the new research, Dr. Dalen said, "I think it would be presumptuous to assume that it would settle anything, given how contentious the field is."