The story ends with a dog curled up at the foot of a bed, having been fed and patted by its owner. But exactly how the canine-human relationship began is a mystery. When and where were dogs first domesticated? For what purpose? How different are they from their fiercer canine relatives, the wolves?
Some clues can be gleaned from dogs and wolves themselves, as well as from fossils of early canids. And in the last decade or so, genetic data have come into play. A 2002 study showed that the greatest genetic diversity in living dogs and wolves (as measured in the mitochondrial genome and later in the Y chromosome) exists in southern East Asia. That led some to finger that region as the birthplace of dogs. But a 2010 study, which used a different kind of genetic analysis to look at 48,000 gene markers in living animals, suggested a close relationship between dogs and Middle Eastern wolves.