An unprecedented survey of the genetic diversity that existed among wolves at the end of the Ice Age has just shed more light on the origins of the long love story between dogs and humans.
The data indicate that most dogs alive today are more closely related to ancient wolves that lived in eastern Eurasia, in places like Siberia, although other populations of the species apparently also contributed to the ancestors of today’s domestic animals.
The results, recently published in the British scientific journal Nature, do not fully resolve the enigma of dog domestication, but they bring a great deal of new information on the subject.
“The dataset of the article is quite impressive. We have about 70 genomes sequenced [ou seja, ‘soletrados’ na Ãntegra, como o genoma humano atual] over a time series of 100,000 years. This allowed us to analyze an enormous amount of detail about how wolves evolved over this period. And, of course, one aspect of that is their relationship to domesticated dogs,” explains David Stanton, a researcher at the Center for Paleogenetics at Queen Mary University of London, in an official statement.
He is one of the co-authors of the study, carried out by an international team of dozens of scientists, most of them European.
Wolves thousands or tens of thousands of years old that “donated” their DNA for the study have a wide geographic distribution. Their skeletons come from much of Western Europe, Russia, the Middle East, Central Asia, and North America.
In fact, wolves were one of the most widely distributed large mammal species on the planet in the Pleistocene (the Ice Age), at which point they resembled the humans who would eventually domesticate some of them. This geographic distribution, a sign of great versatility, may help to explain the fact that the animals did not disappear at the end of this period, unlike many other Pleistocene predators, such as cave bears and saber-toothed animals. .
“It’s amazing how they were able to move relatively quickly and easily through many regions,” noted Stanton in an official statement.
Another possible key factor was revealed by genomic analysis: the frequent connection between wolf populations over time. Apparently, reproduction involving different groups of the species worked as an efficient “wireless phone”, carrying new mutations in DNA from one corner of the Northern Hemisphere to another, especially if they took place in Siberia.
The Siberian territory appears to have been the place that most “exported” wolf genes to wolf populations elsewhere on the planet. With this facility for mixing and incorporating genetic novelties, the animals may have increased their ability to adapt to new environmental challenges over time.
The situation seems to have changed for wolves from 10,000 years before the present, a time when agriculture and animal husbandry were beginning in several parts of the world, with an increase in human population density. This could mean that, from that moment on, members of our species caused environmental changes that reduced the territory available to wolf packs and prevented them from continuing to contact each other.
The genomic data also indicate that the ancestors of dogs alive today were still part of a single “big family” with wolves, at least as far as DNA is concerned, 28,000 years ago. That could be the date for the start of the domestication process, which would mean that dogs came to live with humans about 20,000 years earlier than any other animal. Even so, the authors of the new study note that the process may have even started before then.
A more detailed comparison of ancient wolves with modern members of their species and dogs further revealed that no current wolf population matches that of the possible ancestors of domestic dogs. Dogs are closer to the wolves that existed in eastern Eurasia at the end of the Ice Age, in general. But dogs from the Middle East and Africa would derive up to half of their DNA from other ancient wolves, closer to those living in the westernmost part of Eurasia today.
This may indicate that dogs were domesticated twice, in the East and in the West, or that only eastern domestication occurred, to which later crosses with western wolves were added (since crossbreeding between wolves and dogs is relatively common). . It is not yet possible to say which of the two scenarios is more likely.
