Those tiny, fluffy dogs walking down the street may look cute but beware — they probably have some wolf in them.That is the discovery announced on Monday by U.S. scientists, who were surprised to find that nearly two thirds of all dog breeds have a detectable amount of wolf DNA.And it is not genetic leftovers from when dogs originally evolved from wolves around 20,000 years ago, but instead suggests that domesticated dogs and wild wolves have interbred within the last few thousand years.This does not...