Prehistoric dog genomes reveal diversification and spread of species, alongside humans, in Paleolithic era

Dogs and humans have lived alongside each other for so long, unravelling the history of when the relationship between the two mammals began is a tricky task.

But new research, examining the genome sequences of ancient dogs from up to 11,000 years ago, sheds more light on the history of the species and humans’ role in engineering “man’s best friend”.

A research team lead by Anders Bergström, a postdoctoral fellow of the Francis Crick Institute, sequenced 27 ancient dog genomes from across Europe and Asia, and have found that at least five major dog lineages had already diversified and spread worldwide by 11,000 years ago, suggesting “a considerable genetic history during the Paleolithic era”.

“The dog is the oldest domesticated animal and has a very long relationship with humans. Therefore, understanding the history of dogs teaches us not just about their history, but also about our history,” Dr Bergström said.

Previous research has estimated dogs most likely evolved from wolves at a single location about 20,000 to 40,000 years ago, but lack of genetic material has made tracing the time and location of the split difficult to pinpoint.

To date, very few whole dog and whole wolf genomes stretching back further than a few thousand years have been available for analysis, the researchers said.

“While the antiquity of the inextricable bond between dogs and humans is well recognised, its origin - where and when it began - remains shrouded in history.”

“As a result, very little is known about the population history of prehistoric dogs and how it relates to humans.”

But the new analysis, which compared the newly sequenced ancient genomes to other ancient and modern dog genomes, revealed that all dogs share a common ancestry distinct from present-day wolves.

It also found that since the original ancient split from wolves, there has been limited gene flow from wolves to dogs, but substantial dog-to-wolf gene flow.

The researchers also compared the ancient dog genomes with ancient human genome-wide data from similar time frames, revealing aspects of dog population history that likely reflect their migration alongside human groups, as well as instances where population histories do not appear to align.

Together, the findings “underscore dogs’ complex common history” with humans, the researchers said.

They said the study builds on previous research into the domestication and early history of dogs, including a 2016 study which revealed “a deep split” between dogs from Western Eurasia and east Asia, and a 2018 study which showed the first dogs of North America arrived alongside humans and were not domesticated from North American wolves, but rather, from an ancient breed of Siberian sled dog.

The research is published in the journal Science.