We are not local ourselves…
Scientists have revealed the history of the appearance and death of the first dogs in America
Sergey Vasiliev, Naked Science
The oldest remains of dogs in America were discovered in the middle of the last century on the territory of Illinois and date back to the age of about 10 thousand years. However, that population has disappeared, and modern dogs here are descendants of those brought from Europe and Asia. Were the first dogs in America related to them, or were they domesticated independently? Until now, this question has remained unclear – the answer to it is given only by the recent work of a large international group of scientists published in the journal Science (Leathlobhair et al., The evolutionary history of dogs in the Americas).
The authors were able to extract and decode mitochondrial DNA (mtDNA) from 71 animal remains found in North America and Siberia, and compare these data with mtDNA sequences of 145 ancient and modern dogs already available in open databases. This work showed that up to 1000 years ago, "native American" dogs formed a single group, genetically close to the dogs found in Yakutia, at the Paleolithic site on the island of Zhokhova.
According to scientists, the last common ancestor of "native" American dogs lived about 14.6 thousand years ago, and the common ancestor of them and dogs from Zhokhov Island – 15.6 thousand years ago. Interestingly, the last date coincides with one of the most likely dates of the arrival of people to America through the Bering Strait.
To test their findings, the scientists also turned to the main, nuclear genome, which is much more complex and larger than the mitochondrial one – and more difficult to work with. Such data was obtained for seven remains of "native" American dogs, and they were again compared with their available genomes from databases. The previous conclusions were confirmed: these animals came from a single population and were closer to the dogs of Eastern Siberia (such as huskies) and the Arctic (malamutes) than most of the current dogs in North America.
Subsequently, these dogs disappeared under the pressure of three fatal events for them. The first was the appearance of "Arctic" dogs that came from Siberia about 1000 years ago together with representatives of the ancient Eskimo culture of Tula. The second is the arrival in half a thousand years of Europeans and new dogs from Europe. The third was the mass production of Eurasian running dogs during the gold rush and the development of the northern regions of the USA and Canada in the XIX century.
All this has led to the complete disappearance of "native" American dogs, so that even chihuahuas and other breeds considered "local" do not contain genetic markers characteristic of the first quadrupeds in America. The only trace of them that scientists managed to find was preserved in the cells... cancer. Transmissible venereal tumor of dogs is one of the rarest examples of contagious cancer known to science. Researchers have already established that these mutant cells originated about 8000 years ago in a single individual and then spread, still posing a deadly danger to animals. It seems that this animal was one of the "indigenous" dogs of North America.
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