Dozens of researchers collaborated for the expansive study. Nuclear DNAs are the ones inherited from both parents while mitochondrial DNAs are the ones being passed down only from mothers to the offspring.
Through DNA testing of dogs, the remains of which 10 thousand years, scientists have found that all dogs living on the American continent, descended from the ancestor from Siberia to mainland domesticated wolves came during the glacial era along with the hosts. These remains were sourced in the Americas, revealing that a rapid decline in the indigenous dog population took place following the arrival of settlers.
The oldest bones extracted from a grave in western IL had already been radio carbon dated to just under 10,000 years old, thousands of years after the first signs of human inhabitation on the North American continent.
Previously, experts suggested the domestication of wolves in North America.
Researchers could not find any trace of ancient dog DNA in modern-day village dogs from South America or pre-Columbian breeds like the xoloitzcuintli, the Mexican hairless dog. Evidence that these dogs were used in sledding, along with suggestions that they were used for hunting and hauling, means that they could have facilitated the early settlement of the Americas.
As Anna Linderholm, an assistant professor of anthropology at Texas A&M University who did much of the genome sequencing said, humans are predisposed to bringing their dogs along with them, and Europeans also brought their dogs when they discovered the New World. A third introduction occurred in the 19th century, when Siberian huskies were imported as sled dogs during the Alaskan gold rush. "We suspect that a lot of the reasons [ancient] dogs were wiped out, were similar reasons that Native American populations were destroyed", Perri said.
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The oldest known domestic dog remains in the Americas are approximately 9,900-year-old skeletons in IL. They likely came over in a wave of migration only about 1,000 years ago-roughly 500 years before the Europeans arrived-meaning that they are a little more closely related. Pre-contact dogs were present as the first travellers journeyed from Siberia into the Americas and began to thrive.
The CTVT cells, in which ancient American dog DNA is fossilised. These pre-contact dogs were widespread across the continent, varying in size and shape, and were largely the only domestic animals associated with Native American groups.
Oddly enough, scientists found that the closest surviving trace of pre-contact dogs' DNA is found in a sexually transmitted canine cancer.
Dogs have been man's best friend for more than 10,000 years, but a new study shows it has been a doggone tough road to get here: their ancestors in the Americas likely came from Siberia, and these early dog populations nearly totally disappeared, but not before leaving a cancerous tumor that is still found in their canine descendants today.
"By looking at genomic data along with mitochondrial data, we were able to confirm that dogs came to the Americas with humans, and that almost all of that diversity was lost - most likely as a result of European colonization", Kelsey Witt, who led the mitochondrial DNA genome research as a graduate student at the University of IL, said in a news release.
Though there's still plenty of research to be done in untangling the genetic history of humanity's best friend, the study brings more clues to the table, according to Krishna Veeramah, a geneticist at Stony Brook University who has studied ancient dog evolution. "Few modern dogs have any trace of these ancient lineages".