Genomic insights into the population history of circumpolar Arctic dogs

Sammanfattning: The Siberian and North American Arctic have both borne witness to numerous migrations of humans and with them their dogs. This PhD thesis is based on whole genome data from 22 Siberian dogs and 72 North American Arctic dogs, in addition to 186 mitochondrial genomes Siberian and North American Arctic dogs. Mitochondrial genome data allowed for the identification of migration events that introduced distinct dog populations to North America, associated with different cultural complexes arriving to the region. A novel mitochondrial clade was also identified in dogs from eastern Siberia and Alaska. Genetic analysis was performed to confirm the macroscopic identification of fur used to make clothing in the Arctic in conjunction with stable isotope analyses to explore dietary differences of dog populations across the circumpolar region. The whole genome data generated for this PhD also detected and explored evidence for several gene flow events from West Eurasian dogs into the dogs of Siberia starting 10,900 BP. There was an additional gene flow event that introduced Near East related ancestry to the dogs of the Siberian Steppe before the Late Bronze Age. Dogs carrying this West Eurasian ancestry spread throughout Siberia, reaching northwestern Siberia by the Iron Age, by 2,000 BP. Further gene flow was detected later in Siberia from West Eurasia a thousand years later. North American Arctic dogs universally carry the Near East related ancestry that is seen in Siberian dogs starting in the Bronze Age, showing it had reached the Bering Strait before the ancestors of the Inuit departed Siberia for Alaska. Once in North America Inuit dogs experienced several other gene flow events from pre-contact subarctic dogs, modern European dogs, and wolves. The population structure seen in North American Arctic dogs reflects geography and the subsequent isolation as well as population turnover events associated with catastrophic epidemics in the dog populations. Finally, a simple method was developed to evaluate and remove human contamination from ancient DNA datasets originating from faunal taxa. All together this thesis has compiled genomic information from 94 Arctic dogs to shed light upon the genetic history of these dogs from the early Holocene through to the present day. This dataset has been able to provide insight not only into past dynamics of Arctic dogs but also a much needed resource for understanding and preserving the indigenous dog populations still present in the Arctic that face continued challenges of globalisation and climate change.