How was ancient dog domesticated?
An ancient canine skull unearthed in the mountains of Siberia suggests that modern domesticated dogs may have originated for multiple ancestors in various geographic locations rather than as the result of a single event in a single culture, a new study published in the journal PLoS One claims.
According to BBC News Science Reporter Hamish Pritchard, a Russian-led team of archaeologists discovered the 33,000 year old specimen in the Altai Mountains. That fossil, combined with dog remains that are roughly the same age that were recovered from a cave in Belgium, suggests that the domestication of dogs did not happen at one single location.
While the skull, which is from just before the peak of the most recent ice age, has a snout similar in size to fully domesticated Greenland dogs from about 1,000 years ago, the large teeth more closely resemble those of the 31,000-year-old wild European wolf, Pritchard added.
"Essentially, wolves have long thin snouts and their teeth are not crowded, and domestication results in this shortening of the snout and widening of the jaws and crowding of the teeth," Greg Hodgins, a researcher at the University of Arizona's Accelerator Mass Spectrometry Laboratory and co-author of the study, said in a statement Monday.
"The argument that it is domesticated is pretty solid," he added. "What's interesting is that it doesn't appear to be an ancestor of modern dogs," and that because the fossil was exceptionally well preserved, the scientists were able to measure the skull, the teeth and the mandibles multiple times.
Evolutionary biologist and study co-author Dr. Susan Crockford elaborated in an interview with Pritchard, saying that the dog was in the first stages of domestication, and that the wolves "were not deliberately domesticated, the process of making a wolf into a dog was a natural process."
Both the Siberian specimen was dated using radiocarbon dating at the University of Arizona's Accelerator Mass Spectrometry Laboratory, and the researchers believe that neither that species nor the Belgium one survived the period known as the Last Glacial Maximum (LGM), according to a university press release.
"The two earliest incipient dogs from Western Europe (Goyet, Belguim) and Siberia (Razboinichya), separated by thousands of kilometers, show that dog domestication was multiregional, and thus had no single place of origin (as some DNA data have suggested) and subsequent spread," the researchers wrote in their study.
Credited as authors on the study were Nikolai D. Ovodov and Yaroslav V. Kuzmin of the Siberian Branch of the Russian Academy of Sciences; Susan J. Crockford of Pacific Identifications, Inc.; Thomas F. G. Higham of the Oxford University Research Laboratory for Archaeology; Gregory W. L. Hodgins of the University of Arizona; and Johannes van der Plicht of the Groningen University Center for Isotope Research.