The Last Glacial Maximum Played a Major Role in Dog Domestication.

Indigenous siberian with a laika. This is not a Native American with a Native American dog. However, a new study reveals that Siberia could be the point of origin for the domestic dog. It also the first dogs
 in the Americas came with Siberian hunter-gatherers 15,000 years ago.
 

A new study  released in PNAS today revealed that dogs were domesticated around 23,000 years ago in Siberia. This study, which looked at ancient DNA from dogs and humans from Eurasia and North America, revealed that Siberia is likely the point of origin for dog domestication. Further, the authors were able to demonstrate that ancient North America dogs derive from this Siberian population, entering North America around 15,000 years ago, which is roughly the same time that the first humans entered the continent.

The authors contend that 23,000 years ago roughly coincides with the last glacial maximum, which could have put increased pressure on humans and the wolves that led to dogs to form the relationships that eventually gave rise to domestic dogs. 

The findings of this study are pretty unique, because they come from a pretty well-designed analysis of ancient dog remains. And there is comparison to human dispersal in the late Pleistocene.

A 2013 study in PLOS One revealed that the remains of a 33,000-year-old canid from a cave in the Altai mountains was a dog, and this creature was closely related to the ancient American domestic dogs.

These findings seem to be somewhat contradictory, and I think we need to be careful in assuming that the origin for the domestic dog has somehow been find at long last.

It is possible that the authors are picking up on in the new study is the role the last glacial maximum played in creating a distinct dog lineage.

Mark Derr in his book How the Dog Became the Dog posits that the last glacial maximum was instrumental in creating the distinct "dog" morphology in domesticated wolves, but it is very possible- and it is pretty likely-- that ancient humans had a relationship with wolves going back deeper than the 23,000 years posited in the study.

Indeed, the authors of the new study point out that the last glacial maximum could have isolated these wolves from other wolves, allowing for a more rigorous selection for great symbiosis with humans.

This idea is quite intriguing, because it is very likely that human and wolf relationships in Eurasia go much deeper than the ones that ultimately lead to dog domestication as we know it now. For example, we have several examples of ancient European "dogs" that date to around 31,000 years ago, including one in what is now the Czech Republic that was apparently interred with a bone in its mouth.

So it is very possible that the lineage of wolves that became modern dog lineages was finally made distinct from other gray wolves 23,000 years ago, but we likely have several periods of domestication and semi-domestication that stretch across Eurasia for thousands of years before the last glacial maximum. Some of these domesticated and semi-domesticated wolves could have rejoined the wild population, and wild genes could always be filtering in. 

The truth of the matter is that after reading Pierotti and Fogg's wonderful book on dog domestication, one wonders if we will ever know when dogs became distinct from wolves. But it would be reasonable that the last glacial maximum could have played a role in that transition.