According to professor Merete Fredholm with the University of Copenhagen, scientists used to believe that all dogs were descended from a single wolf pack in China. Recent research however indicates that many different civilizations domesticated dogs at different times. Meanwhile researchers at Durham University in England are discovering that modern dogs do seem to be exclusively descended from gray wolves. There has been so much crossbreeding in recent history however, that modern dogs have little genetic resemblance to their canine ancestors and tracing a direct link back from one breed directly to a wolf is next to impossible.