A fragment of a 10,000-year-old dog bone found along the coast of Alaska could be the oldest evidence of domestic dogs in North America, and possibly evidence of a coastal route traveled by the first humans to travel from Eurasia to North America. entered.
The evidence continues to pile up for the Coastal Migration Theory, which states that instead of traveling through an interior passageway between two melting ice sheets, Eurasian migrants embraced the Siberian, Beringian and Alaskan coasts. These settlers continued their way along the Pacific coast, eventually reaching the southernmost limit of the massive Cordilleran Ice Sheet, according to this theory.
The Coastal Migration Theory, also known as the Kelp Highway Hypothesis, is supported by geological and archaeological evidence, including 29 human footprints found on the coastline of Calvert Island in British Columbia. We now have more evidence to support this theory, but it comes from an unexpected source: a domesticated dog.
This dog died about 10,150 years ago in what is now Alaska during the end of the last I.what age. The lone fossil – a piece of a femur – is now the oldest confirmed remains of a domestic dog in America, according to the new research, led by University at Buffalo evolution biologist Charlotte Lindqvist. The article describing this discovery was published Tuesday in Proceedings of the Royal Society B.
G / O Media can receive a commission
That Alaska received dogs around this time is no big surprise. 2019 research presented proof Of the three prehistoric dogs buried in what is now Illinois, which were dated between 9,630 and 10,190 years ago, the latest figure suggests a date slightly older than the date presented for the femur in the new document. I asked Lindqvist about this apparent discrepancy.
“If you compare the median radiocarbon dating of the Illinois dogs and our dog, the Alaskan dog is a little older,” she said. “But it depends on what you’re comparing, and with the error bars and uncertainty – and the radiocarbon dating done by various labs – you can say they are at least about the same age, possibly with the Alaskan dog being several hundred years older. “
The Illinois dogs are important in that they suggest that the early settlers of North America brought their dogs from Eurasia. Previous genetic Research done in this area came to a similar conclusion, showing that dogs arrived in America about 10,000 years ago.
Lindqvist and her colleagues accidentally stumbled upon the femur while sequencing DNA from a tangle of bones from animals excavated in caves in southeast Alaska. This research is done to determine how the climate changes during the last I.what age affected several species, including their mobility.
“One of the projects I’m working on involves black and brown bears and we initially thought the bone came from a bear, but later we found out it was a dog, and we had to act on this finding,” explains Lindqvist in an email.
The dog femur fragment, designated PP-00128, was found on southeastern mainland Alaska, just east of Wrangell Island in a location known as Lawyer CaveLindqvist, with her co-author Timothy Heaton, a professor of earth sciences at the University of South Dakota, conducted a number of excavations in the late 1990s and early 2000s, resulting in the discovery of this bone and many others from the same cave.
The team was able to derive a complete mitochondrial genome from the fragment, which they compared to modern dog breeds, historic Arctic dogs, and American pre-contact dogs (ie, dogs that lived in America before the arrival of Europeans). Mitochondrial DNA comes exclusively from the maternal side, so it is incomplete (compared to nuclear DNA), but the scientists were able to trace the genome back to a lineage that diverged from Siberian dogs about 16,700 years ago.
This is important, as this “timing roughly coincides with the minimum proposed date for the North Pacific coast opening. Cordilleran Ice Cap route and genetic evidence for America’s first populations, ”the authors wrote in the study.
Indeed, the PP-00128 fragment provides yet another clue in favor of the coastal migration hypothesis. The coastal edge of the ice sheet began to melt about 17,000 years ago, while the walk inland didn’t open until about 13,000 years ago
Previous genetic estimates of the split between pre-European American dogs and their Siberian ancestors were younger than estimates from when the ancestral Native American human population diverged from their Siberian ancestors, suggesting dogs arrived in later migrations of humans to America, perhaps even along the inland corridor, ”explained Lindqvist.
Before the new study, “the oldest American dog remains were found in sites in the middle of the continent, which doesn’t suggest how they got there,” she said, but this latest discovery “supports that our coast dog is a descendant of dogs that took part. to this first research.migration along the northwestern Pacific coast.
There is, of course, a possibility that this was a rogue dog that somehow made its way to North America without people. That’s not as strange as it may seem; dogs were domesticated by wolves between 14,000 and 29,000 years ago, in a complex process involving multiple interbreeding episodes between dogs and wild wolves. That said, Lindqvist believes her Alaskan dog likely lived with humans.
Other remains excavated in the same cave include human bones and artifacts, but these are all younger, ”she said. However, they do suggest that the cave was indeed used by humans. And from human remains found in another cave in southeast Alaska, we know there were people in the region when this ancient dog lived. But no, we have no direct evidence that this dog lived in humans. However, we know that this dog was a domestic dog and not a wolf, and if I were a dog I would probably stay with people to eat. “
Indeed, a carbon isotope analysis of the femur fragment suggests this dog was fed by humans while eating fish (possibly salmon), and meat from whales and seals. This is in stark contrast to other ancient dogs that lived in the middle of the continent, who had a “much more earthy diet,” Lindqvist said.
It seems very likely that people traveled along the Pacific coast of Eurasia to North America, and the new research fits nicely into this increasingly popular story. But that doesn’t mean that alternative roads to the continent were neglected. As previous research shows, there probably was more than one route to North America, as an inner corridor was likely opened some 12,600 to 13,100 years ago.