Wed. Jan 29th, 2020

Revealed the origin of the dogs that conquered the Arctic | Science

In Alaska there is a site called Nunalleq that is like a time capsule. Here the land has remained frozen for centuries and what comes out of it is amazingly preserved. Archaeologist Rick Knecht has found amber notches, wooden masks and, above all, ropes made of dried grass that was cut more than 400 years ago or, as he says, when Shakespeare was still on Earth.

These strings speak of one of the toughest and most unknown chapters of the expansion of humans across the planet. About 2,000 years ago, the eskimos – a group of nomadic hunters from Siberia – launched themselves into the conquest of the Arctic, arriving first in Alaska and then traveling along the east coast of Canada and to Greenland, where they arrived about 800 years ago.

The most surprising thing is that they managed to survive generation after generation until today, the only human group that has succeeded. None of this would have been possible without the dogs pulling their sleds. The ropes found in Nunalleq they were actually sled harnesses and even kept dog lice. In Nunalleq there were even bones of a puppy that died crushed when the roof of the cabin fell before being put to the load.

Now, a team of archaeologists and geneticists have analyzed the skulls of 391 dogs found in human settlements up to 4,500 years ago to date to try to clarify the origin of those sled dogs that, together with two boats, kayak and umiak, allowed Eskimos, or Inuits, survive in one of the most hostile places on the planet.

Rick Knecht of the University of Aberdeen, with one of the harnesses discovered in Nunalleq (Alaska).

Rick Knecht of the University of Aberdeen, with one of the harnesses discovered in Nunalleq (Alaska).

"We are possibly facing the greatest history of cooperation between dogs and humans," said Tatiana Feuerborn, a researcher at the Center for Paleogenetics at the University of Stockholm and the Natural History Museum of Sweden and co-author of the study, just published by the Royal Society. "The first settlers of America came across the Arctic more than 15,000 years ago, but they did not settle there," he explains. “Then came the Paleo-Inuit people, about 4,000 years ago. These people did stay for hundreds of years but did not use sleds or boats and eventually disappeared from the area. The first evidence of sled use came with the Inuit. So far it has not been possible to know if they arrived in the Arctic and trained the dogs that were already in this area or brought their own dogs, ”explains the researcher.

The study shows that the Eskimos developed their own breed of specialized dogs and with them they reached the Arctic. More than best friends were "living tools," says Feuerborn. They not only pulled the load but also hunted, watched and even served as food when hunting was scarce or even by pure gastronomic whim, depending on the work. Their morphology was different from that of the dogs that brought the paleoinuit. They were bigger dogs, with narrower heads.

The team has also analyzed the mitochondrial genome, which passes from mothers to children, of almost 1,000 dogs and wolves. The results confirm that the origin of Inuit dogs is in Siberia. The work also shows that the DNA of this breed of dogs is still present in Greenland's sled dogs, which are the closest thing there are to ancient Inuit dogs today. These dogs can have their days counted. Their number has been drastically reduced by the fragmentation of the territory by climate change, the growing preference of Eskimo hunters for snowmobiles and the ravages of distemper and parvovirus, according to alerted a recent study. Only 15,000 left.

One of the analyzed dog skulls found in an Inuit site in Greenland.

One of the analyzed dog skulls found in an Inuit site in Greenland.

When Europeans arrived in the Arctic in the nineteenth century they said that Eskimos crossed their dogs with wolves to give them strength. The anthropologists who began studying these cultures a century later told the same stories. In theory, the Eskimos preferred that it was their dogs that preyed on a wolf, not the other way around. But DNA analysis has not found traces of Inuit dogs having wolf DNA. This does not mean that there was not, but it was probably not a common practice, perhaps on purpose. "The stories of hybridization between wolves and dogs are very common in Greenland today, but these same sources say that hybrids are usually bad sled dogs and that breeders try to avoid wolf features," the authors write. In addition, the number of crossings between wolves and dogs has been limited over thousands of years, judging by the genetic flow between both species, which “makes it unlikely that any resemblance between Inuit dogs and Arctic wolves is the result of crosses, ”they add. The last word will be the nuclear DNA analysis of dogs and wolves, a task that the Feuerborn team is already working on.

"This is a study with a huge interest and very well done," he says Pat shipman, retired paleoanthropologist at Pennsylvania State University. “Currently, dog breeders that are used for sled races in Alaska maintain two lineages, one very fast, the other very resistant. It is possible that the Inuit did exactly the same, ”he says.

Shipman believes that "perhaps it is an exaggeration" to consider this chapter as the most important cooperation between dogs and humans. “I maintain the theory that the successful invasion of Europe by modern humans and their permanence during the ice age to the detriment of the Neanderthals, which became extinct, was facilitated by the domestication of the dog, which happened about 40,000 years ago ”, Shipman adventure.

Greenland sled dogs, the current breed more similar to the one used by the Eskimos to conquer the Arctic 1,000 years ago.

Greenland sled dogs, the current breed more similar to the one used by the Eskimos to conquer the Arctic 1,000 years ago.

"The domestication of the dog is one of the most fascinating and unknown events in the history of mankind," acknowledges Elisabetta Cilli, an expert in ancient DNA at the University of Bologna (Italy). Contradictory studies have been published in recent years, some that maintain that there was only one domestication about 40,000 years ago, others that point to at least two in different places in Eurasia, at least 12,000 years ago. “We currently have very few certainties. I think it happened in several places at the same time, but it is a very complex problem that we will be unraveling in part thanks to paleogenetic analyzes like this, ”Cilli points out.

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