When were dogs domesticated? Oldest known dog DNA offers clues

Dogs in Europe have been domesticated from wild wolves by at least 14,200 years agosuggest two new genetic studies.

The two studies, published on March 25 in Natureuse ancient DNA recovered from fossil dog bones to revise the early history of domestic dogs (A family dog). Research pushes back confirmed date of separation of dogs and wolves (Dog lupus) more than 3,000 years old.

The two studies represent a “significant advance” in understanding how dogs evolved from wolves, says evolutionary biologist Beth Shapiro of the University of California, Santa Cruz, who was not involved in the new work. And they show that living dogs are the result of more than 15,000 years of migration, interbreeding and human influence, she says.

Dogs were the first animals domesticated by humans – tens of thousands of years before horses, sheep or cattle – and share many of their genes with wolves. Scientists believe that dogs evolved from wolves, primarily to be less aggressive toward humans, but the exact date of their genetic divergence is not known.

A 2015 study estimated that dogs separated from the wolves between 27,000 and 40,000 years old, based on fossilized Siberian wolf bones radiocarbon dated to around 35,000 years ago. And, until now, oldest confirmed dog remains with preserved DNAfound in northwestern Russia, dates to around 10,900 years ago.

Researchers in the latest studies examined ancient DNA extracted from more than 200 sets of dog and wolf remains at dozens of prehistoric sites in Europe, southwest Asia and the Iranian plateau. The oldest dog in both studies comes from the Kesserloch archaeological site in Switzerland, radiocarbon dated to 14,200 years ago, during the Paleolithic period. Genetic analyzes show that the Kesserloch dog shared ancestry with Paleolithic dogs from other regions, suggesting that dogs were then widely established and genetically distinct from wolves.

The second study examined dog genomes from ancient sites in what is now Turkey, England and Serbia, and shows that genetically stable dog populations had spread across this region around 14,300 years ago.

Fossilized dog bones from many sites also showed consistent genetic signatures, suggesting they belonged to established, stable populations. Researchers aren’t sure if any of these ancient dogs were technically pets of the prehistoric humans who lived at the sites or if the dogs were just “hanging out at human campsites,” says geneticist Anders Bergström of the University of East Anglia in Norwich, England. But there is archaeological evidence that at least one of the dogs had been well cared for by humans, suggesting the dogs were good-natured members of their group, he says.

The results of the two studies reinforce the idea that dogs evolved from wolves between 27,000 and 40,000 years ago. But both refute the idea that European dogs are independently descended from European wolves. Instead, the data “show that these early European dogs shared the same origins as dogs elsewhere and reached Europe 14,000 years ago,” says Bergström.

Bergström and his coauthors also found traces of Southwest Asian ancestry among some ancient European dogs, which could reflect Southwest Asian origin. migration of farmers from this region to Europe. And the authors of the second study note that the remains of genetically similar dogs were often found among the remains of genetically different human groups. This finding suggests that the spread of dogs was linked to the migrations and interactions of human groups.

The latest studies offer further evidence for the idea that dogs had a single origin, perhaps somewhere in Asia, with later crossbreeding between early dogs and wolves, says Adam Boyko of Cornell University, who studied dog genetics but was not involved in the new studies. “Of course, we cannot rule out that some of the first fossils classified as wolves were actually tame and efficient dogs,” he says. “But from the point of view of modern dogs, it seems that they all share a common origin of domestication.”

The more we can study ancient canine DNA, Shapiro says, the closer we will come to answering the question of when and where our remarkable partnership with dogs began.