DNA from a 9,500-year-old dog from Siberia clarifies the origins of modern sled dogs.
Dogs play an important role in human life all over the world—whether as a family member or as a working animal. But where the dog comes from and how old various groups of dogs are is still a bit of a mystery.
“We have extracted DNA from a 9,500-year-old dog from the Siberian island of Zhokhov, which the dog is named after. 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,” says co-first author of the study Mikkel Sinding, a PhD student at the Globe Institute, part of the University of Copenhagen’s Faculty of Health and Medical Sciences.
The research from the QIMMEQ project took place in collaboration with the University of Greenland and the Institute of Evolutionary Biology, Barcelona. Their research appears in Science.
Huskies, malamutes, and sled dogs
The common belief has been that Zhokhov was a kind of ancient dog—one of the earliest domesticated dogs and a version of the common origin of all dogs. But according to the new study, modern sled dogs such as the Siberian husky, the Alaskan malamute, and the Greenland sled dog share the major part of their genome with Zhokhov.
“This means that modern sledge dogs and Zhokhov had the same common origin in Siberia more than 9,500 years ago. Until now, we have thought that sledge dogs were only 2,000-3,000 years old,” says co-first author Shyam Gopalakrishnan, an associate professor at the Globe Institute.
To learn more about the origins of the sled dog, researchers have further sequenced genomes of a 33,000-year-old Siberian wolf and ten modern Greenlandic sled dogs. They have compared these genomes to genomes of dogs and wolves from around the world.
“We can see that the modern sledge dogs have most of their genomes in common with Zhokhov. 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,” says Sinding.
The modern sled dogs have more genetic overlap with other modern dog breeds than Zhokhov has, but the studies do not show where or when this occurred. Nevertheless, among modern sled dogs, the Greenland sled dog stands out and has the least overlap with other dogs, meaning that the Greenland sled dog is probably the most original sled dog in the world.
Different diets
In addition to advancing the common understanding of the origin of sled dogs, the new study also teaches the researchers more about the differences between sled dogs and other dogs.
Sled dogs do not have the same genetic adaptations to a sugar- and starch-rich diet that other dogs have. On the other hand, they have adaptations to high-fat diets, with mechanisms that are similar to those described among polar bears and Arctic people.
“This emphasizes that sledge dogs and Arctic people have worked and adapted together for more than 9,500 years. We can also see that they have adaptations that are probably linked to improved oxygen uptake, which makes sense in relation to sledding and give the sledding tradition ancient roots,” says Gopalakrishnan.
Source: University of Copenhagen
