The majority view in science today is that all domesticated dogs come from one ancestral dog breed. That may not be the case. Dogs may have been domesticated many times in many places over the millennia. The dogs we have now may be descended from more than one of those breeds of ancestral dog.
The 33,000-year-old skull of a dog was dug up recently in a Siberian mountain cave. It is evidence of early domestication. Together with an equally ancient find in a cave in Belgium, the two fossils indicate that modern dogs may be descended from more than one ancestral dog breed. DNA evidence seems to point to a single ancestor, and for now scientists are puzzled about how to reconcile DNA evidence with fossil evidence. Read the full article.