Toward the end of the last ice age, a group of people armed with stone spears stalked their prey in the freezing cold of northeastern Siberia. These men were tracking herds of bison and woolly mammoths in the vast meadows. Next to them are creatures that look like wolves, but have more friendly personalities and are especially willing to obey, help these people hunt and bring trophies back to the camp.
Perhaps it was the first dogs in the world, and their descendants then followed the flow of human migration, spread east and west and settled on Eurasia, and become companions of the ancestors of the Americas as they migrated.
That’s the scenario laid out in a recent study that combined DNA data from ancient dogs and humans. The results of this study were published in the Proceedings of the National Academy of Sciences. This research is of enormous significance because it could put an end to years of debate about where and when dogs were domesticated. It might even explain how vigilant ancient wolves were transformed into our loyal companions.
“I like this study,” said Jennifer Raff, an anthropologist at the University of Kansas, Lawrence, and an expert on ancient people in the Americas. More genomes from ancient dogs and humans would be needed, she said, to confirm the study’s conjectures, and was also surprised to find dog and human stories interesting. so.
The idea of this research began with a few beers in the office of evolutionary biologist Greger Larson at Oxford University, while he was speaking with Angela Perri, an archaeologist at Durham University, on the origins of ancient dogs in North America, where genetic and archaeological evidence suggests they lived for at least 10,000 years.
Archaeologist David Meltzer, from Southern Methodist University, proposed comparing the ancient DNA of dogs and humans. “He started talking about how and when people divided into different groups after leaving Siberia and arriving in North America” Perri recalled. If the dog’s DNA shows changing patterns similar to the alteration to adapt to human passages, that could reveal when the dog’s story came out and domesticated by humans. . “We found a huge whiteboard and started scribbling arrows in all different directions. It was a mess, but it was quite interesting and told the story of the history of dog domestication.
From those ideas, the researchers analyzed the chronologically ordered mitochondrial genomes of more than 200 canine specimens discovered from around the world, some dating back 10,000. year. Through analysis, these mitochondrial DNA (which are short chains more in fossils than nuclear DNA) showed that all dogs in ancient North America carried a genetic marker – called A2b – and they split into four groups about 15,000 years ago when they inhabited different parts of North America.
The team found that the times and locations of those splits are similar to those of ancient American Indian groups. All of these people are descended from a group that scientists call the ancestors of the Native Americans, born in Siberia about 21,000 years ago. The team concluded that those humans brought the dogs with them when they arrived in the Americas about 16,000 years ago. (But it is a rather painful fact that the ancient dogs of America eventually disappeared when the Europeans arrived in America.)
Going deeper into the genetic past, the team found that the A2b dogs were descended from Siberian dogs about 23,000 years ago. The ancestors of those dogs probably lived with people belonging to the genetic group known as ancient Northern Siberians. This group of people appeared more than 31,000 years ago, lived in a relatively temperate part of northeastern Siberia for thousands of years, prevented by extreme climates from moving too far east or west. difficult and slow. There is archaeological evidence that this group of people shared their habitat with the ancient gray wolf, which is believed to be the direct ancestor of today’s gray wolves and domestic dogs.
The leading theory of dog domestication holds that certain groups of ancient gray wolves have increasingly come closer to human camps in search of leftovers, and the shyest meek ones have advanced. transformed over hundreds or thousands of years into the gentle puppies we know today. But this is not entirely true when humans migrate too far continuously for a short period of time and encounter new wolves. It is therefore possible that the original domestication of dogs only took place in a small group in a certain area.
Furthermore, archaeological evidence suggests that ancient dog breeders may have exchanged animals for ancestors of Native Americans, as well as for other groups of humans, including humans. further west into Eurasia. That may explain why dogs appeared in both Europe and North America around 15,000 years ago. It can be said that this is a puzzle that led scientists to speculate that dogs have been domesticated many times. Instead, all dogs were descended from 23,000-year-old puppies in Siberia, the team argued.
But based on all she knows about ancient people in America, Jennifer Raff argues that the research underlying story is “true.” However, she notes, mitochondrial DNA represents only a small portion of the animal’s genome and “cannot fill in the overall picture of evolutionary history without the nuclear DNA.”