This suggests that dogs have a single, rather than a multiple origin. The only domestic dog that varies is the Arctic Elkhound, which appears to have evolved separately. These new studies, done by Robert Wayne, a University of California-Los Angeles evolutionary biologist shows wolves are the closest species to the domestic dog. This is the largest study ever done in this field, and includes 140 domestic dogs, covering 67 purebreds and 4 crossbreeds. This was compared to samples of DNA collected from 162 wolves, in 27 localities worldwide.
Wolves are members of the carnivore family, known as canis lupus.
The domestic dog is also of the carnivore family, known as canis familiaris. The differences between the two are not great enough to make it necessary to postulate a hypothetical ancestral wild species which has neither survived to the present day not left any known fossil remains. Some typical features common to carnivores are a large mouth opening, a single hinge joint that lays in the same plane as the teeth, and a large primary muscle on the side of the head for operating the jaw. The teeth are short and pointed, made for grasping and shredding. These teeth come together to give a cutting motion and act like shears.