Gray wolves (Canis lupus), and wolves in general, are not dogs (Canis lupus familiaris) although they share the same genus and species. Interestingly, In 1993, genetic research led to the reclassification of the older name for dogs, Canis familiaris, to Canis lupus familiaris -- showing Fido and Spot to be domesticated wolves. Domestic dogs branched from their wolf ancestors on the way to becoming man's best friend many thousands of years ago.
When Wild Dogs Became Companions
Though science has yet to pinpoint an exact date when humans and dogs began to pal around together, a genetic analysis published in the "PLOS Genetics" journal, concludes that dogs were probably roaming with hunter-gatherers between 11,000 and 16,000 years ago. This study postulates that dogs and wolves may not be ancestors and descendants so much as parallel groups, like sisters or cousins, whose common wolf ancestor became extinct long before dogs were domesticated. It also speculates that a particular mutation in dogs, allowing them to digest starches as well as meat, may have contributed to dogs' domestication by allowing them to eat foods similar to those humans were eating -- although that mutation appears to be absent in huskies and dingoes.
Where Dogs Came From
The "PLOS Genetics" study compared genomes of three extant wolf species from Asia, Eastern Europe and the Middle East to several modern dog breeds and wolf subspecies. However, the study cannot be considered conclusive without including other known wolf species. None of the wolves in this study group proved genetically closer to modern dogs than any other. All the dogs proved more closely related to other dogs than to wolves, and the wolves were all more closely related to one another, regardless of geographic origin, than they were to any of the dogs -- making these wolf species unlikely ancestors of domestic dogs. That mystery remains unsolved. The lack of the starch mutation in dingoes and huskies also raises questions about the precise time of domestication. Whether they joined mankind with the rise of agriculturalists, whose diet would have contained significantly more starch, or had an evolving role in the lives of the primarily meat-eating hunter-gathers is unclear. Without further research, the jury may still be out.
All the Same
Whether purebred tiny Chihuahua, huge St. Bernard or proverbial junkyard dog, all domestic dogs are the same subspecies of animal, Canis lupus familiaris. While purpose-driven dog interbreeding has existed for as long as canines have associated with humans, that cute little Pekingese in your lap is as close to being a wolf as is her wild-looking sister the Siberian husky.
Purebred vs. Mixed-Breed
The distinction between a purebred dog and a mixed-breed dog is one of genetic manipulation. Two separate breeds mating produce mixed-breed litters. But when two animals having the same purebred status mate -- two purebred standard poodles, for instance -- their offspring will also be purebred. The same goes for wolves. If a gray wolf mates with a gray wolf, the pups will be gray wolves. Because dogs are a wolf subspecies, breeding between the two produces a fertile Canis lupus cross known as an intraspecific hybrid -- not a hybrid in the usual infertile sense, but also not a purebred of either, since domestic dogs are not a distinct species from wolves. The so-called wolf-dog is an example of this type of breeding.