Ten years ago, we feared Tasmanian devils would be wiped out by a bizarre infectious facial cancer transmitted by biting. But new genetic analysis shows they are evolving to live with the disease.
There is speculation about whether a population can achieve some sort of immunity to the virus with as little as 20% infected.
Every time the virus copies itself it makes mistakes, creating a trail that researchers can use to build a family tree with information about where it's traveled, and when.
Comparing genomes of more than 200,000 people, researchers identified genetic variants that are less common in older people, suggesting natural selection continues to weed out disadvantageous traits.