The relationship began—well, nobody knows exactly when it began. The earliest remains of humans and dogs interred together date to 14,000 years ago, but some unconfirmed finds are said to be more than twice as old. The larger point is the meaning of the discoveries: we lived with dogs and then chose to be buried with them. Imagine that.
It was only by the tiniest bit of genetic chance that our cross-species union was forged at all. Dogs and wolves share 99.9% of their mitochondrial DNA—the DNA that’s passed down by the mother alone—which makes the two species nearly indistinguishable. But elsewhere in the genome, there are a few genetic scraps that make a powerful difference. On chromosome six, in particular, investigators have found three genes that code for hyper-sociability—and they are in the same spot as similar genes linked to similar sweetness in humans.
DOG FOOD SECRETS
