Domestic dogs evolved from a group of wolves that came into contact with European hunter-gatherers between 18,800 and 32,100 years ago and may have since died out.
This origin story comes from a new study that compares DNA from dozens of dogs and wolves, including 18 ancient fossils.
The results, published today (November 14) in Science, provide the clearest picture yet of where, when, and how wild predators came to be man’s best friend.
“It really is a sea change from the little bits of fragmentary DNA that have been reported in the past,” said Gregor Larson from Durham University in the U.K., who was not involved in the study. “It includes really old material from a wide range of sites.”
The new paper follows two earlier studies that looked at the genetic signatures of domestication in dogs, and came to differing conclusions about canine origins.
One group suggested that dogs were domesticated around 10,000 years ago during the Agricultural Revolution, when wolves started scavenging human scrap heaps.
Another concluded that wolves and dogs split 32,000 years ago, somewhere in East Asia.
Both studies compared the genes of a wide variety of living dogs and wolves, but modern samples can be deceptive.
Dogs and wolves diverged so recently that many of their genes have not had time to separate into distinct lineages.
They have also repeatedly hybridized with each other, further confusing their genealogies.
To deal with these problems, a team led by Olaf Thalmann from the University of Turku in Finland analyzed mitochondrial DNA from 18 fossil canids.
They compared these ancient sequences to those from 49 modern wolves and 77 modern dogs, and built a family tree that charts their relationships.
The tree conclusively pinpointed Europe as the major nexus of dog domestication.
It identified four clades of modern dogs, which are all most closely related to ancient European canids rather than wolves from China or the Middle East.
“We didn’t expect the ancestry to be so clearly defined,” Thalmann told The Scientist.
“This suggests that the population of wolves in Europe that gave rise to modern dogs may have gone extinct, which is plausible given how humans have wiped out wolves over the centuries,” he added.
According to this new tree, the largest clade of domestic dogs last shared a common ancestor 18,800 years ago, and collectively, they last shared a common ancestor with a wolf around 32,100 years ago.
They must have been domesticated at some point during this window.
These molecular dates fit with fossil evidence.
The oldest dog fossils come from Western Europe and Siberia, and are thought to be at least 15,000 years old.
By contrast, those from the Middle East and East Asia are believed to be 13,000 years old, at most.
“The archaeologists would be happy,” said Larson.