Domestic dogs probably first arrived in North America with early human settlers from Siberia, only to be wiped out by Europeans half a millennium ago.
Using genome sequences from archaeological remains and modern breeds, Laurent Frantz at the University of Oxford, UK, and his colleagues constructed an evolutionary tree for dogs. They found that the earliest dogs in North America were not domesticated from local wolves, but probably arrived alongside humans who migrated there between 17,000 and 13,000 years ago.
The genomes of modern dogs show almost no connection to those of the earliest American dogs, which were most closely related to Arctic breeds such as Siberian huskies. This suggests that the early population was wiped out when European settlers arrived in the New World in the fifteenth century. The early dogs’ only genetic legacy might be a contagious genital cancer that infects modern domestic dogs. The cancer's genome bears similarities to the genome of the first American dogs, the authors say.