Man's best friend gained that title in Europe, according to a new study that pinpoints the origin of dog domestication to between 18,800 and 32,100 years ago.
The study places the origin of dogs before the rise of agriculture, suggesting that human hunter-gatherers tamed the wolf. Whereas previous genetic studies had placed the origin of dogs in the Middle East or Asia, this research is the first to focus on the genetics of ancient dogs, rather than looking at modern dogs and trying to extrapolate back.
"All modern dogs analyzed in our study were closely related to either ancient dogs and wolves from Europe or modern wolves from there," study scientist Olaf Thalmann, a postdoctoral researcher at the University of Turku in Finland, told LiveScience in an email.
The beginning of dogs
Dogs are the only large carnivores that humans have ever domesticated, but when and where dangerous wolves became lovable pups has been hard to pin down.
That's because, genetically speaking, dogs are a mess. They've been moved around the world for centuries, mixing their genomes indiscriminately at far-flung ports of call, and even -- early in their evolution -- mating with their wild counterpart, the wolf. Adding to the confusion is the intensive period of selective dog breeding that started in the late 1880s and gave humans the wide variety of dog breeds known today. [What Your Dog's Breed Says About You]
Archaeologists have found definite evidence of domestication in the form of dogs and humans buried together at least 14,000 years ago. Some have suggested domestication occurred earlier than that, perhaps as long as 33,000 years ago, based on some doglike skulls found in Belgium and in Siberia.
Original genetic analyses put dog domestication much earlier, with researchers writing in a 1997 paper in the journal Science suggesting that dogs diverged from wolves more than 100,000 years ago.
Those studies compared modern dogs with modern wolves. However, the analysis was muddied by dogs' weird breeding history. In the new study, published Friday (Nov. 15) in the journal Science, scientists analyzed ancient DNA from prehistoric dog fossils found in Europe and the New World.
The researchers sequenced mitochondrial DNA from these fossils. Mitochondria are tiny organs inside cells that generate the energy that cells need to run. The genes that control the mitochondria are passed down the maternal line.
Comparing the ancient mitochondrial DNA with the mitochondrial DNA of modern dog breeds and wolves revealed a common link to Europe, the researchers found.
"Dogs seem to have been domesticated or first evolved from a population of ancient wolves living in Europe," said study researcher Robert Wayne, a professor of ecology and evolutionary biology at the University of California, Los Angeles. "That ancient wolf population is now extinct."