The scientists examined samples of mitochondrial DNA, which is inherited only from the female, in 27 different wolf populations and 67 dog breeds, as well as from coyotes and jackals.
The tests showed that during most of the late Pleistocene Era, from 600,000 to 12,000 years ago, humans and wolves coexisted in many regions of the world. The key change would have occurred between 15,000 and 10,000 years ago, as the last Ice Age was ending and humans invented farming to replace hunting as a food source.
"The change from nomadic hunter-gatherer societies to more sedentary agricultural population centres may have imposed new selective regimes on dogs," say the team, led by Robert Wayne of the University of California at Los Angeles. Essentially, dogs and wolves would no longer have been able to interbreed - locking dogs into the genetic patterns they now exhibit. The work is reported today in the journal Science.Reuse content