Scientists have analyzed the ancient DNA of wolves, which was stored in permafrost for tens of thousands of years, and were able to shed light on the process of dog domestication. This analysis showed that humans have tamed these animals twice, according to Science Alert..

All dogs in existence today, from the tiny Chihuahua to the Mastiff, belong to the same species, Canis familiaris.. And they all come from a common ancestor of wolves, including the modern gray wolf, Canis lupus.. But the timing of domestication is debatable. Some scientists suggest that this process began 100,000 years ago..

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In previous work, scientists studied DNA samples of 32 dogs, whose age is 100-32 thousand years.. They found that dogs diversified 11,000 years ago, which means domestication must have started earlier.. Domestication is known to have begun between 40,000 and 20,000 years ago.. This process probably happened more than once and in different parts of the world..

In the new work, the researchers studied 72 genomes of wolves, whose age was up to 100 thousand years.. They covered about 30 thousand generations of wolves in Europe, Siberia and North America.. These genomes were compared with 68 genomes of modern wolves, ancient and modern dogs, and other canine species such as coyotes..

The analysis showed that both ancient and modern dogs have more in common with the ancient wolves of Asia, and not those that lived in Europe.. This suggests that domestication and diversification may have started in the East rather than the West..

But the researchers also found something odd.. Early dogs in northeastern Europe, Siberia and America get 100% of their DNA from the eastern wolf population. Early dogs from the Middle East, Africa, and southern Europe have wolf DNA associated with modern populations in Southeast Eurasia.

This confirms earlier findings that dogs have been domesticated more than once.. But it could also mean that dogs were first tamed in the East and then crossbred with wild wolf populations.. However, it has not yet been possible to determine which of these scenarios is reliable..

The study also allowed scientists to learn more about the evolution of wolves.. In particular, they found that the IFT88 gene variant has gone from very rare to ubiquitous over the past 10,000 years.. It is responsible for the development of the bones of the head and jaw, and is still present in almost every dog \u200b\u200bor wolf..

At the moment, scientists cannot say why this mutation has become so common.. It may have to do with natural selection: the types of food available have made the changes brought about by the mutation especially beneficial.. It is also possible that this gene is responsible for some processes that are still unknown to scientists, which makes the mutation even more significant..

Previously, scientists found that ancient European dogs between 8,000 and 2,000 years ago became twice as large.. Thanks to this, they could protect livestock from wolves and bears..