Researchers from the University of Illinois at Urbana-Champaign have proven that the first dogs that lived in the Americas were descended from Siberian dogs, not wolves. These dogs came with their human counterpart as they migrated over the land bridge linking Siberia with Alaska.
According to the researchers few if any modern dogs are related to these ancient dogs. It appears that the dogs died out after people from Europe came to the Americas.
They also discovered “. . . that the genomic signature of a transmissible cancer that afflicts dogs appears to be one of the last “living” remnants of the genetic heritage of dogs that populated the Americas prior to European contact.”
This latest research brings up the question of the heritage of the Carolina Dog which claims to be descended from the original dogs that were brought to North America across the Bering Strait. It would have been interesting if the researchers included this breed of dog in their study.