Sled dogs are closely related to 9,500-year-old 'ancient dog'
Sled dogs are older and adapted to Arctic conditions much earlier than previously thought.
In a new study from the QIMMEQ project, researchers from University of Copenhagen and University of Greenland show that the modern sled dog has worked and lived with humans for over 9,500 years.
Dogs play an important role in human life around the world - whether as a family member or as a working animal. But where the dog comes from, and how old different groups of dogs are, remain a bit of a mystery.
Now light is shed on the origins of the sled dog. In a new study published in SCIENCE, researchers from the Faculty of Health Sciences, University of Copenhagen, show that the sled dog is both older and adapted to the Arctic far earlier than previously thought.
"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 dog genome ever, i.e. mapped the entire canine genome, and the results show an extremely early differentiation of dog types and diversity," the study’s first author, postdoc Mikkel Sinding says.
Until now, the common belief has been that the 9,500-year-old Siberian dog, Zhokhov, was a kind of 'ancient dog' - one of the earliest domestic dogs and a version of the common origin of all canines. But according to the new study, modern sled dogs such as Siberian Husky, Alaskan Malamute and the Greenlandic sled dog have most of their genome in common with Zhokhov.
"This means that modern sled dogs and Zhokhov have the same common origin in Siberia over 9,500 years ago. Until now, we have thought that sled dogs were only 2-3,000 years old," Mikkel Sinding says.
The original sled dog
To understand the origins of the sled dog, researchers have further sequenced genomes from a 33,000-year-old Siberian wolf and 10 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 sled dogs have most of their genome in common with Zhokhov. In other words: they are more closely related to this 'ancient dog' than they are to other dogs and wolves. But not only that - we can see traces of mixing with wolves like the 33,000-year-old Siberian wolf - but not modern wolves. This further emphasizes that the origins of the modern sled dog go back even further than we thought," Mikkel Sinding says.
The modern sled dogs have more genetic overlap with other modern dog types than Zhokhov has, but the studies do not tell us where or when this happened. Nevertheless, among modern sled dogs, the Greenlandic sled dog stands out and has the least overlap with other dogs - meaning that the Greenlandic sled dog probably is the most original sled dog in the entire world.
Common features with Inuit and polar bears
In addition to advancing the common understanding of the origins of sled dogs, the new study also made the researchers grow wiser in respect to the differences between sled dogs and other dogs. Sled dogs do not have genetic adaptations to a sugar- and starch-rich diet that other dogs otherwise have. On the other hand, they have adaptations to consume high-fat diet, with mechanisms similarly described to polar bears and Arctic peoples.
"We can also see that they have adaptations that are probably linked to improving oxygen uptake, which makes good sense when it comes to sledding. All of which emphasizing that sled dogs and Arctic people have worked together and adapted for over 9,500 years," Mikkel Sinding says.
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