The first animal people domesticated was our best friend, the dog. That makes for some very old specimens when looking at the origin of the species. Prehistoric samples of dogs have been found in Germany, and have previously shown that they became distinct from wolves at least 15,000 years ago. New work analyzing the genomes of two prehistoric dogs found in Germany has indicated that these two genomes are likely the ancestors of contemporary European dogs.
This work, an international collaboration led by Krishna R. Veeramah, Ph.D., of Stony Brook University also suggests that modern dogs probably have a common origin, emerging after a single domestication process in wolves 20,000 to 40,000 years ago. The report, which had contributors from Johannes Gutenberg University Mainz (JGU), was published in Nature Communications.
The archaeological record of dogs is not reliable; previous work has suggested that dogs were domesticated at different times and places. Some research in this area was done on bones of domesticated dogs that had been unearthed from a remote Siberian island. Other findings have suggested dog domestication events occurred in both Asia and the Near East. Work last year analyzed the genome of a 5,000-year-old dog sample found in Ireland.
That research, by scientists at the University of Oxford also showed that two domestication events happened. The investigators from that study hypothesized that migration from East Asia replaced the indigenous domesticated dogs of Europe during the Neolithic period. This new work contradicts that idea.
"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," explained Veeramah, Assistant Professor of Ecology and Evolution at Stony Brook University. "This suggests that there was no mass Neolithic replacement that occurred on the continent and that there was likely only a single domestication process for the dogs observed in the fossil record from the Stone Age and that we also see and live with today."
For this study, the research team had two samples; the 7,000-year-old dog specimen was used to narrow the window of domestication to 20,000 to 40,000 years ago. A second sample that was 4,700 years old showed a genetic mixture of European dogs and modern Central Asian and Indian dogs. This result helps show that when Asians began migrating to Europe around the start of the Bronze Age, they brought their pups along.
"Our study shows how the analysis of entire ancient genomes can help us to gradually understand complex processes, such as dog domestication. Only direct insights into the past like this enable us to disentangle the effects of the many parallel and successive events that are involved, including targeted breeding by humans as well as population movements and admixture of multiple populations," noted report author Dr. Amelie Scheu, a research assistant in the Palaeogenetics Work Group of the Institute of Organismic and Molecular Evolutionary Biology at Johannes Gutenberg University Mainz.
The exact location of dog domestication remains a mystery. Veeramah is confident that additional genetic sequencing will eventually reveal the answer.
Learn more about how domestication affected dogs from the video.
Sources: AAAS/Eurekalert! Via JGU, Science, Nature Communications