Genomics: Gray wolf genome hints at dual ancestry of dogs

Dogs are more closely related to ancient wolves from eastern Eurasia than to those in the west, according to an analysis of ancient wolf genomes spanning the last 100,000 years from Europe, Siberia and North America. In this analysis, published this week in Nature, researchers were able to detect natural selection throughout the Late Pleistocene (between around 129,000 and 11,700 years ago).

The gray wolf (Canis lupus) was the first species to give rise to a domestic population and was present across most of the northern hemisphere throughout the last Ice Age when many other large mammals went extinct. Although it is clear that dogs came from gray wolves, there is no consensus regarding when, where and how this happened.

To elucidate this history, Pontus Skoglund, Anders Bergstrom and colleagues sequenced 66 new ancient wolf genomes from Europe, Siberia and northwestern America, and included five previously sequenced ancient wolf genomes and an ancient dhole genome (a wild dog native to Central, South, East, and Southeast Asia) from the Caucasus from over the last 100,000 years. The authors found that wolf populations were genetically connected throughout the Late Pleistocene, which was likely due to the wolves’ ability to move across an open landscape. This connectedness among the wolf populations allowed the authors to identify natural selection, specifically the rise of mutations in the gene IFT88 40–30 thousand years ago, which may have contributed to the survival of the species. The traits from IFT88 responsible for this survival advantage remain unclear.

The authors found an eastern Eurasian-related species that appears to have contributed to around 100% of the ancestry of early dogs in Siberia, the Americas, East Asia and Europe. However, they also found that dogs in the Near East and Africa developed up to half of their ancestry from a distinct population related to modern southwest Eurasian wolves, which signifies either an independent domestication or breeding with local wolves. None of the analyzed genomes are a direct match for either of these dog ancestries.

Further research into additional ancient wolf genomes from other regions of the world will be necessary to further identify the ancestors of modern day dogs.