The transformation of wolf to dog: history, traits, and genetics
The dog may be our most diverse and remarkable living invention. The diversity of dogs in size and proportion exceeds that of the entire carnivore order, including more than 270 species. Functional diversity is also impressive, with specific dog breeds having enhanced sensory, locomotor and cognitive abilities. However, perhaps the most meaningful attribute of dogs is their eagerness to do useful work for humans. These tasks are as varied as their form, including guarding, rescue, warfare, hunting, herding, transport and companionship, mirroring the functions of individuals in human society. Consequently, understanding the historical development of this parallel will enlighten study of human evolution. I present a historical perspective on dog evolution, as probing the context of first domestication is essential to predicting the effect of historical contingency on subsequent evolution. The timing and context of dog domestication is controversial with various analyses supporting China, the Middle East or Europe as centers of origination from gray wolves. Similarly, the timing varies from less than 10,000 to as much as 100,000 years ago. I present data which suggests past analysis are flawed as they make the implicit assumption of origin from an ancestor closely related to modern wolves followed by limited back-crossing. Our results of mitochondrial DNA from ancient wolves and dogs, and recent analysis of complete nuclear genome sequencing instead suggest an origin from a now extinct form of European wolves more than 20,000 years ago which is followed by persistent interbreeding with wolves. These findings place domestication at time and place when humans were migratory hunter-gatherers and suggest a unique domestication scenario applies to the dog, the only large carnivore ever domesticated.