The skeleton of a dog native to the Americas.
American dogs are still present in at least one form — researchers discovered that a common form of transferable cancer among dogs bears traces of American dog DNA. Canine transmissible venereal tumors is one of only three known kinds of cancer that can spread from a host to another mammal.
"CTVT originated from the cells of a single dog, known as the 'CTVT founder dog,' that lived several thousand years ago. Remarkably, the research revealed that the dog that first spawned CTVT was closely related to American pre-contact dogs. Overall the results indicate that this cancer, now found worldwide, possesses a genome that is the last remaining vestige of the dog population that was once found all across the Americas," the news release said.
The study also made discoveries about the origins of American dogs.
Dogs native to the Americas did not come from American wolves but rather originated in Siberia and crossed the Bering Strait with the waves of human migration that settled the American land mass. They spread throughout both continents and became "an integral part of so many Native American cultures," Laurent Frantz from Queen Mary University of London said. Frantz is one of the study's lead authors.
More then 10 millennia of isolated evolution meant that American dogs developed "genetic signatures unlike dogs found anywhere else in the world," the news release said.
The research is scheduled to be published in Science, one of the world's premier academic journals, on Friday and will be titled "The Evolutionary History of Dogs in the Americas."