Jul
9
2018

Indigenous North American peoples endured horrible suffering and devastating loss at the hands of European settlers who began arriving in the New World in the early fifteenth century.

Indigenous North American dogs may have had it nearly as bad.

According to new research, ancient dogs, who arrived in the Americas alongside humans more than 10,000 years ago and dispersed throughout North and South America, were almost completely wiped out by European colonization.

Using DNA from 71 archaeological dog remains from North America and Siberia and genetic material from 5,000 modern dogs, an international team led by researchers at the University of Oxford in England showed that ancient (or “precontact”) American dogs possessed genetic signatures unlike dogs found anywhere else in the world.

But when the researchers compared the genomes of ancient and modern American dogs, they discovered that these precontact American dogs rapidly disappeared following the arrival of Europeans and left little to no genetic trace in modern American dogs.

Senior lead author Laurent Frantz, PhD, MSc, said: “It is fascinating that a population of dogs that inhabited many parts of the Americas for thousands of years, and that was an integral part of so many Native American cultures, could have disappeared so rapidly. Their near-total disappearance is likely due to the combined effects of disease, cultural persecution, and biological changes starting with the arrival of Europeans.”

Angela Perri, PhD, the study’s lead archaeologist and co-first author, told online science blog Live Science that, “We suspect that a lot of the reasons [ancient] dogs were wiped out were similar reasons that Native American populations were destroyed.”

Those reasons include introducing nonnative diseases such as canine distemper and rabies to the New World (similar to how settlers introduced nonnative diseases like smallpox to the indigenous human population); a world view that saw native dogs as pests to be freely killed, or, when game animals were scarce, as a food source; and a probable reluctance to interbreed what they thought of as their “prized” European dogs with “mongrel” native ones.

But while indigenous North American dogs may have vanished, they haven’t vanished without a trace.

They’ve left behind a nasty surprise—a kind of genetic pawprint in the form of a transmissible cancer.

Canine transmissible venereal tumor (CTVT) is a contagious genital cancer that is spread between dogs by the transfer of living cancer cells, usually during mating. CTVT is a common disease found today in dogs around the world, but the new research revealed that the CTVT genome originated in a single dog, called the founder dog, who lived several thousand years ago—a dog who was most likely a precontact North American dog.

“It’s quite incredible to think that possibly the only survivor of a lost dog lineage is a tumor that can spread between dogs as an infection,” said Máire Ní Leathlobhair, a PhD candidate at the University of Cambridge in England and co-first author of the study. “Although this cancer’s DNA has mutated over the years, it is still essentially the DNA of that original founder dog from many thousands of years ago.”

As far as legacies go, it’s a grim one.

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