Man’s companions were the first of many animals that man domesticated. But there is never a clear before and after moment where the dogs suddenly become a distinct pack of wolves. While some of the ancient skeletons were clearly dogs, there were many mysterious skeletons before that. It is possible to find out what happened using the genome Modern and ancient dogs. But that analysis relies heavily on what you think comes from the wolf dog form.
Now, researchers have got a clearer picture of the last 100,000 years of wolf evolution. The picture he paints is that of a population that remains a unit despite being spread across the continent in the Arctic, with populations that have sporadically recovered from a core centered on Siberia. Many dog breeds appear to have descended from the East Asian wolf pack. But others also appear to have received important Middle Eastern input – but it’s not clear if this is a pack of wolves or dogs.
Wolves around the north
The ability to sequence ancient DNA was critical to this new work, including obtaining DNA from 66 wolf skeletons that collectively span some 100,000 years of evolution, including most of the last Ice Age. Wolves are found in the Northern Hemisphere, and the skeletons used here tend to be closer to the Arctic (perhaps in part because their DNA survives better in colder climates). But it is widely distributed, with representatives in Europe, Asia and North America. The researchers also included five ancient wolf genomes analyzed by others, along with several modern wolf genomes.
You would normally expect to find regional populations that don’t mix very often with their distant relationships. If you identify the most closely related genomes, you will usually find that they are clustered together. This is not the case here. Instead, the genomes of ancient wolves were clustered together in time. That is, it is most likely a wolf that is closely related to another wolf that lived at the same time, no matter where on the planet they lived.
Studies of modern wolves have shown that local populations evolved after the last peak of the last Ice Age. But all of these populations are more similar to each other than the wolves that existed before the peak of the Ice Age.
How did these animals maintain genetic continuity over the great distances that separated them? Apparently, with the frequent expansion of the population in Siberia. There was a distinct population of European wolves somewhere 100,000 years ago. But continued arrivals from Siberia gradually reduced the presence of European ancestors to between 10 and 40 percent, depending on the animal. In contrast, in North America, all present-day wolves originate primarily from Siberia, and the remainder is contributed by interbreeding with coyotes.
One consequence of having a global population is that beneficial mutations spread rapidly throughout the world. The researchers found 24 genomic regions that appear to carry favorable adaptations, and all of these beneficial DNA stretches appeared in all the wolf groups examined.
gold for dogs
So, what can we say about dogs? They also look like Siberian wolves that lived before the last peak of the Ice Age. But when every wolf larger than that point was tested for close relationships with dogs, the relationships weren’t as strong. This suggests that if dogs belong to a particular group of wolves, we do not have DNA from that group.
But the researchers found a good match if you had a population of Siberian wolves with a small portion of their DNA (between 10 and 20 percent) that came from a different species, wormholes, also found in Asia. It seems that several dog breeds in East Asia retain these origins to this day.
But other subspecies in Europe and Africa appear to have had a significant contribution from wolves, which are closely related to today’s wolves from Syria. Researchers estimate that a dog from the Middle East about 7,500 years ago had about half its genome from this local source and half from its Siberian ancestor. Many dogs in Africa and Europe share 20 to 60 percent of their genome from this additional ancestor.
Taken together, their data support a model in which dogs were first domesticated in East Asia, where most of the existing breeds derive only from Siberian ancestry. But since our close friend had spread out with us throughout Asia, he had come into contact with other residents, most likely near the Middle East. It could be a pack of wolves, or it could be a group of separately domesticated dogs, or it could be somewhere in between – there’s no way of knowing the genetic data.
However, the wolf data provide some context for why it is difficult to classify canine ancestry: genetically, wolves are not unusual for having a global population that regularly reproduces in a way that disrupts long-term stable territorial groups. One consequence is that there is little benefit in studying a pack of wolves that are closely related to dogs as a way of determining where dogs were tamed. Even if that wolf population existed at that time, it was likely that they would soon mix with another population.
temper tantrums2022. DOI: 10.1038 / s41586-022-04824-9 (About DOI).
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