Describe how selective breeding of wolves has lead to the breeds of dogs we see today?

Well, what happened was that you had populations of dog-wolves that became isolated from the greater wolf population and in doing so, they began to breed more closely-to inbreed as it were. And when you inbreed, you get genetic peculiarities that arise, and those peculiarities then begin to become part of the population ... In other words, a mutation will appear in a small population.