paulsamuel said:
The research is very recent. It just made it into National Geographic last year. It hasn't had time to filter down into all the publications and websites.
The difference in DNA between a mongrel dog and a wolf is less than that between two extreme breeds of dog, say a Basset hound and a Saluki. Moreover, it is
far less than the difference between a human from Norway and one from Borneo, whom we regard as a single species.
Dogs and wolves are like reindeer and caribou: one species, but over thousands of years a few noticeable differences have been selected in the domesticated population.
Wolves are simply one breed of dog: the original.
All dogs are descended from a wolf population in China. The wolves there today have the same genetic markers that all dogs have. That means that wolves joined humans in a multi-species community in just one place, and humans took their dogs with them everywhere they went and/or traded them with other tribes, rather than repeating the process of domestication all over the planet.
The only major, consistent differences between a dog and a wolf are:
1. The teeth halfway back in their jaws (I don't remember what they're called) have lost the blade-like shape that allows wolves to easily rip the meat off a fresh kill, and instead are shaped more like molars for a scavenging lifestyle.
2. Their brains are a bit smaller. Brains need a lot of protein, and the diet of a scavenger does not provide as much as that of a nearly full-time predator.
3. They almost instinctively accept humans as equals and even pack leaders, whereas to wolves we are competitors at best, enemies at worst.
All of the other differences in the various breeds are the result of selective breeding (some of which goes back 8,000 years almost to the dawn of civilization) and can easily be mixed back into a dog that looks pretty much like a dingo in just a couple of generations of hybridization.
As for the question about dogs being able to crossbreed with wolves. This does not make them the same
species, it makes them the same
genus. (Such as horses, asses, and zebras; or bison, steers, and Asian buffalo.) Being the same species, these days, seems to be a judgment call on the part of the zoological community, and they're revising their taxonomies wholesale since the advent of DNA analysis. Dogs/wolves, coyotes, and jackals are the three best known members of genus Canis. Dog-coyote hybrids are quite common in the Southwest. Wolf-coyote hybrids have established populations where their ranges overlap on the fringes of civilization in the East. Jackals (which are more than one species) don't live in our hemisphere so I don't know anything about their breeding habits.
However, the new taxonomies play havoc with the traditional definition of a genus. None within the dog family Canidae, but plenty within Felidae, the cats. Housecats and ocelots used to be counted as genus Felis, as were the lion and tiger. Now the lion and tiger are in a new genus Panthera, and the ocelot is in a new genus Leopardus. The problem is that housecats and ocelots can be easily crossbred. You can find ocicats in the want ads in any big city newspaper. How can they interbreed if they're in two different genera?
I've been asking that question for ten years and nobody has given me an answer. The same thing happens with parrots. The hyacinth macaw (the poster child of the endangered species movement) is genus Anodorhynchus and the blue-and-gold macaw (the most popular pet macaw) is genus Ara. Yet they have been successfully hybridized.
Dogs are wolves. Wolves are dogs. It will take a while for thousands of books on dogs to be rewritten.