The first domestication of dogs would have appeared somewhere in Asia

An international team of geneticists and archaeologistsdirected by Francis Crick Institute (United Kingdom), found that the ancestry of dogs can be traced back to at least two ancient wolf populations. Thus, these domestic animals would be more related to the wolves from the ice age eastern Eurasia than western ones, according to an analysis of gray wolf genomes over the last 100,000 years from Europe, Siberia, and North America.

“Our finding that dogs are more closely related to prehistoric wolves in Asia than to those in Europe suggests that the domestication process may have taken place somewhere in Asia. We can’t say more precisely where exactly, because we don’t have ancient wolf genomes from much of the continent. But we think it is an important step to be able to determine the origin of dogs”, points out SINC Anders Bergstromco-author of the work published by the journal Nature.

For the researchers, this work marks another step towards unraveling the mystery of dog domestication, one of the biggest unanswered questions about human prehistory. Scientists were able to detect natural selection throughout the late Pleistocenebetween about 129,000 and 11,700 years ago.

“Studying the genomes of ancient wolves allows us to understand how these predators are genetically related to each other and to dogs, but not how they were biologically. Therefore, we cannot say much about the characteristics of the wolves that gave rise to the dogs”, says Bergström.

What is known for sure is that gray wolf (kennel lupus) was the first species to give rise to a domestic population and was present in most of the Northern Hemisphere during the last Ice Age, when many other large mammals became extinct. Domestication would have occurred at least 15,000 years ago.

Dogor, an 18,000-year-old wolf cub from Yakutia, was included in the study. / Sergei Fedorov

A sequencing of 72 ancient wolf genomes

To learn more about its history, the team sequenced 66 new genomes of ancient wolves from Europe, Siberia and Northwest America, including five more previously sequenced wolf genomes and a genome from a dhole – a wild dog native to the central, southern, eastern regions. and Southeast Asia – from the Caucasus in the last 100,000 years. The remains include a complete and perfectly preserved head of a Siberian wolf that lived 32,000 years ago.

The fossils come from previously excavated prehistoric wolves, and archaeologists from 38 institutions in 16 different countries participated in the study. Then nine ancient DNA labs collaborated to generate DNA sequence data from the wolves.

“Our goal was to get the largest possible sample of ancient wolves, but there are big differences between different parts of the world in terms of the availability of these animals as well as their DNA conservation. In many remains, it is simply not preserved, so a study like this involves looking at many different fossils and getting lucky with some of them.”

The fact that most of the ancient wolf genomes in this work come from northern latitudes is a reflection of how DNA is better preserved in cooler climates.

The unknowns about the double offspring are still open

By analyzing the genomes, the researchers found that early and modern dogs are genetically more similar to ancient Asian wolves than those of Europe, suggesting a taming somewhere in the east.

However, they also found evidence that two different populations of wolves contributed DNA to the dogs. The first ones from northeastern Europe, Siberia and the Americas appear to have a single, shared origin with the eastern source. But those from the Middle East, Africa and southern Europe would have an ancestry from another source related to the Middle East wolf in addition to the eastern source.

A possible explanation for this dual ancestry is that wolves were domesticated more than once and that different populations intermingled. Another possibility is that domestication occurred only once and that the dual ancestry is due to these early dogs mixing with wild wolves. It is currently not possible to determine which of these two hypotheses occurred.

“With this project, we have greatly increased the number of sequenced ancient wolf genomes, allowing us to create a detailed picture of wolf ancestry over time, including the time of the dog originsBergström emphasizes.

A 32,000-year-old wolf skull from Yakutia whose genome has been sequenced. / I love Dalen

Natural selection and genetic mutations

They also found that wolf populations were genetically connected throughout the Late Pleistocene, likely due to wolves’ ability to move in an open landscape.

This connection between wolf populations allowed the authors to identify natural selection, specifically the increase in mutations in the IFT88 gene between 40,000 and 30,000 years ago, which may have contributed to the species’ survival. The characteristics of the IFT88 responsible for this survivability advantage remain unclear.

“We know from studies in mice and humans that the IFT88 gene is involved in skull and jaw development. Although we can’t be sure why natural selection targeted this gene in Ice Age wolves. We speculate that this may have reflected some sort of morphological adaptationperhaps in response to changes in prey availability or hunting strategies,” says Bergström.

Many potential prey species became extinct during the Ice Age. Changes in facial or mandibular morphology conferred by mutations in IFT88 may have allowed wolves to adapt to new conditions during this ecologically turbulent period.

Per Pontus Skoglundco-senior author and group leader of the Ancient Genomics laboratory at Crick: “This is the first time that scientists have directly followed natural selection in a large animal on a time scale of 100,000 years, seeing how evolution in real time , rather than trying to reconstruct it from the current DNA.

The team continues the search for a close ancestor of the wolf of dogs, which could more accurately reveal where domestication took place. They are now focusing on genomes from other locations not added in this study, including regions further south.