How to Build a High-Altitude Superdog

No need to start from scratch. Here, someone else already took a wolf and made you a perfectly serviceable sea-level dog. With some genetic tweaking, you can craft a powerful pet that isn't bothered by living on an oxygen-starved mountaintop. A few of the same tweaks to your DNA will even let you live there with it. This is no cockapoo or schnoodle. The Tibetan mastiff and the dog it was bred from, called the Chinese native dog, are ancient breeds, thousands of years old. Tibetan mastiffs live comfortably on the Tibetan Plateau, which with an average elevation of over 4,500 meters is nearly three times as high as Denver. Residents keep the bulky, athletic beasts as guard dogs. Chinese geneticist Ya-Ping Zhang, along with an international group of coauthors, wanted to know what mutations in canine DNA had created this altitude-loving breed. They gathered DNA from 32 Tibetan mastiffs, ...