June 26 (UPI) -- Modern sled dogs are part of an ancient lineage, according to a study published Friday in the journal Science.
Genetic analysis suggests sled dogs emerged much earlier than previously thought, researchers report.
"We have extracted DNA from a 9,500-year-old dog from the Siberian island of Zhokhov, which the dog is named after," Mikkel Sinding, doctoral student at the University of Copenhagen's Globe Institute, said in a news release.
"Based on that DNA we have sequenced the oldest complete dog genome to date, and the results show an extremely early diversification of dogs into types of sledge dogs," said Sinding, one of the authors on the study.
Until now, most scientists assumed Zhokhov was a kind of proto-dog -- an ancient dog. Breeds, researchers estimated, came later.
But when scientists compared the DNA of modern dogs to DNA extracted from the 9,500-year-old dog, they found considerable overlap between the genomes of the Siberian Husky, the Alaskan Malamute and the Greenland sledge dog and the genome of Zhokhov.
"This means that modern sledge dogs and Zhokhov had the same common origin in Siberia more than 9,500 years ago," Shyam Gopalakrishnan, assistant professor at the Globe Institute. "Until now, we have thought that sledge dogs were only 2-3,000 years old."
Researchers also analyzed the genomes of a 33,000-year-old Siberian wolf and ten modern Greenlandic sledge dogs, as well as dogs and wolves from different parts of the world.
"We can see that the modern sledge dogs have most of their genomes in common with Zhokhov," said Sinding. "So, they are more closely related to this ancient dog than to other dogs and wolves. But not just that -- we can see traces of crossbreeding with wolves such as the 33,000-year-old Siberian wolf -- but not with modern wolves. It further emphasizes that the origin of the modern sledge dog goes back much further than we had thought."
The modern sled dogs have more genetic overlap with other breeds than they do with Zhokhov. The Greenland sled dogs have the least overlap with other breeds of any modern breed -- suggesting the Greenland sled dogs were one of the earliest breeds, the original sled dog.