Dogs are believed to have come from wolves that eventually became domesticated. However, scientists have long debated when and where the domestication first began. For example, one study said it started 32,000 years ago in East Asia, while another study said it started 18,000 to 32,000 years ago in Europe.
Now, a new genetic study suggests dogs could have been domesticated first in Central Asia, possibly in Nepal or Mongolia. Using the principle of linkage disequilibrium, Adam Boyko of Cornell University and his team looked at the DNA of 549 village dogs - those that wandered on the streets or around certain locations but were not owned by anyone - from 38 countries.
They found that some village dog populations came from Europe. However, they discovered that many village dog populations, even those that were from Vietnam, India and Egypt, were from Central Asia, indicating that they were first domesticated in that region.
"It's a really comprehensive work including all kinds of markers, and a fairly good geographical coverage," Peter Savolainen, an evolutionary geneticist at the Royal Institute of Technology in Stockholm, told Science. "So, it gives a good picture of the overall genetic relations among today's dogs." Savolainen had previously studied genetic samples of dogs from different parts of the world to determine their birthplace.
However, some scientists do not agree with Boyko's findings, and others question his method of using modern-day genes instead of ancient DNA from fossils.
"The origins of modern populations are extremely messy," Greger Larson from the University of Oxford, who also did a previous study on the origin of dogs' domestication, told The Atlantic. "Thus, it is difficult, if not impossible, to infer the true deeper history of [dogs] by exclusively investigating extant populations, no matter how far flung or deeply sequenced they are."
The study was published in the online Oct. 19 issue of Proceedings of the National Academy of Sciences (PNAS).