THE DOG ENCYCLOPEDIA

Evolution of the dog
There are an estimated 500 million domestic dogs worldwide, and all of them are related.
At the base of their evolutionary tree stands the gray wolf, from which every type and breed of dog has descended.
As geneticists have discovered, in terms of DNA, the difference between wolf and dog is infinitesimal.
While natural selection has produced some of the changes that make one type of dog different from another, the effect of human influence has been far greater.
It could be said that of the hundreds of modern dogs known today, all of them are man-made.