Modern sled dogs - Arctic-adapted breeds like the Greenland sled dog, Alaskan Malamute and Husky - share ancient Siberian roots and represent a distinct genetic lineage that likely emerged as the final glacial remnants of the last ice-age subsided nearly 10,000 years ago. These findings, from a genetic study of modern and ancient Arctic dogs, reveal the antiquity of sled dog breeds and highlight their importance to human survival in the Arctic since the dawn of the Holocene. "Our results imply that the combination of these dogs with the innovation of sled technology facilitated human subsistence" at this time, Mikkel-Holder Sinding and colleagues say. Archaeological evidence from eastern Siberia suggests that Arctic-adapted dogs have likely been integral to human life in the Arctic for at least 15,000 years. Similar to their roles in these regions today, ancient Arctic dogs were used to pull sleds, facilitating long-distance travel and transportation of resources across the harsh, frozen landscape. Despite being one of the most unique groups of dogs, little is known about the modern sled dog's ancient genetic and evolutionary past. Sinding and colleagues sequenced the genomes of 10 modern Greenland sled dogs, an ancient 9,500-year-old Siberian sled dog and a roughly 33,000-year-old Siberian wolf and compared them to a host of other modern dog genomes to assess the genetic origin of the Arctic sled dog. Sinding et al. revealed the ancient Siberian dog as a common ancestor to modern sled dog breeds - particularly Greenland sled dogs, which, due to their isolated populations, can trace more direct genomic ancestry to ancient sled dogs. While the results indicate gene flow from Siberian Pleistocene wolves, unlike many other dog breeds, the authors found no significant admixture between any sled dog - modern or ancient - and American-Arctic wolves, suggesting a roughly 9,500-year genetic continuity in Arctic dog breeds. Sinding et al. also illustrate several convergent adaptations in Arctic dogs, including one that allowed sled dogs to eat the fat-rich and starch poor diets of their human counterparts.
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