image of dog in forest
July 19, 2017

Fossils suggest all domestic dogs trace back to a single wolf population

Given the vastly different appearances of different dog breeds, it might be difficult to accept that all of them can trace their ancestors back to a single group of wolves, but that’s exactly what new research published Tuesday in the journal Nature Communications claimed happened.

In their paper, Dr. Krishna Veeramah, an assistant professor of ecology & evolution in the Stony Brook University College of Arts & Sciences, and his colleagues wrote that DNA collected from a pair of prehistoric dogs from Germany suggested that all modern dogs shared a single origin.

The genomes of those ancient dogs indicate that they were the likely progenitors of modern-day European dogs, the research team said, and their findings counter research published in 2016 that suggested that dogs were actually domesticated on two separate occasions, The Verge noted.

“Contrary to the results of this previous analysis,” we found that our ancient dogs from the same time period were very similar to modern European dogs, including the majority of breed dogs people keep as pets,” Dr. Veeramah explained in a press release. “This suggests that... there was likely only a single domestication event for the dogs observed in the fossil record from the Stone Age and that we also see and live with today.”

More DNA samples needed to end the debate once and for all

While the new study suggests that modern canines were domesticated once, between 20,000 and 40,000 years ago, a different group of scientists published a paper last year which suggested that dogs were actually domesticated twice – once in Europe and once in Asia, with some of the latter dogs eventually replacing some early European dogs, according to Nature and The Verge.

However, after studying a 7,000-year-old dog fossil, as well as two others dating back between 4,700 and 5,000 years ago, and comparing their genome sequences to those of 5,649 wolves and modern dogs, Dr. Veeramah’s team disputes those findings. Instead, they argue that a lone group of dogs were likely domesticated, then later divided into two groups (Eastern and Western).

One of the reasons for the single-domestication conclusion of the new study, The Verge noted, is the fact that the authors of the 2016 two-domestication study shared their data with the authors of the newer paper. The team behind the earlier study reported findings traces of what they believed may have been an earlier, extinct European lineage in a 5,000-year-old Irish dog fossil. However, the authors of the newer paper said that they found no such evidence in the dog’s DNA – instead, they reported finding a technical error they believe tainted the earlier study’s findings.

Dr. Veeramah admits that this is likely far from the end of the debate over the origins of modern-day dogs. “Archaeologists suggest one and geneticists suggest another. People are always getting very different answers,” he explained in an interview with Nature. “More ancient dog DNA from genomes will ultimately solve the problem.”

“If we can add in other ancient samples from all around the world, it'll give us a more comprehensive picture of population history and likely dog origins,” noted Cornell University geneticist Adam Boyko, who was not involved in the research. Those samples, however, must come from different parts of the world and different eras emphasized Boyko, who according to Nature is currently building an international database of canine genomes.

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Image credit: Vincent Munier/naturepl.com