Dogs have ancestry from two different wolf populations

June 29. () –

Geneticists and archaeologists led by the Francis Crick Institute have discovered that the ancestry of dogs can be traced to at least two ancient wolf populations.

This work, published in the magazine ‘Nature’represents one more step towards the discovery of the mystery of the domestication of dogs, one of the biggest unanswered questions about human prehistory.

Dogs are known to have originated from the gray wolf and that this domestication occurred during the Ice Age, at least 15,000 years agous. But it is still unknown where it happened and if it was in one place or in several.

Previous studies using the archaeological record and comparing the DNA of modern dogs and wolves have not found the answer. In the new study, the researchers turned to the genomes of ancient wolves to better understand where the first dogs evolved from wolves. They analyzed 72 ancient wolf genomes, spanning the last 100,000 years, from Europe, Siberia and North America.

The remains came from previously excavated ancient wolves, and archaeologists from 38 institutions in 16 different countries participated in the study. The remains included a complete and perfectly preserved head of a Siberian wolf that lived 32,000 years ago. Next, nine ancient DNA labs collaborated to generate DNA sequence data from the wolves.

Analyzing the genomes, the researchers found that both early and modern dogs are genetically more similar to ancient wolves from Asia than to those from Europe. suggesting a domestication somewhere in the east.

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

One possible explanation for this double ancestry is that wolves were domesticated more than once and the different populations mixed. Another possibility is that domestication occurred only once and that the double ancestry was due to these early dogs mixing with wild wolves. At present it is not possible to determine which of these two hypotheses occurred.they acknowledge.

Anders Bergström, co-first author and postdoctoral researcher in the Crick’s Ancient Genomics lab, says it’s a statement “Thanks to this project, the number of sequenced ancient wolf genomes has increased enormously, allowing us to create a detailed picture of wolf ancestry over time, even around the time of the dog’s origins.” “.

“In trying to fit the dog piece into this picture, we discovered that dogs derive ancestry from at least two separate wolf populations: an eastern source which contributed all dogs and a separate source further west, which contributed some dogs“, Add.

The team continues the search for an ancient close ancestor of the wolf for dogs, which could reveal more precisely where domestication likely took place. They are now focusing on genomes from other locations not included in this study, including more southern regions.

As the 72 ancient wolf genomes spanned some 30,000 generations, it was possible to look back and build a timeline of how wolf DNA has changed, tracking natural selection in action.

For example, they found that over a period of about 10,000 years, a genetic variant went from being very rare to being present in all wolves, and it is still present in all wolves and dogs today. The variant affects a gene, IFT88, which is involved in the development of the skull and jaw bones..

They note that the spread of this variant may have been driven by a change in available prey types during the Ice Age, giving wolves with a certain head shape an advantage. but the gene could also have other unknown functions in wolves.

Pontus Skoglund, lead author and group leader of the Ancient Genomics lab at the Crick, said: “This is the first time that scientists have directly followed natural selection in a large animal over a 100,000-year time scale, seeing how evolution unfolds in real time rather than trying to reconstruct it from current DNA.”

“We found several cases where the mutations spread throughout the wolf species, which was possible because the species was highly connected across great distances,” he continued. This connectivity is perhaps one reason wolves managed to survive the Ice Age while many other large carnivores disappeared.”

“Similar genome-wide time series from the Ice Age, in humans or other animals, could provide new insights into how evolution occurs.”