This Week: Scraps of ancient textiles found
In the News: Mystery of the disappearing ice sheet
The progenitor of canine parvovirus, shown here in glorious molecular detail, once afflicted only cats and their relatives. But in the 1970s, the cat virus reconfigured just two or three surface amino acids and unleashed a plague upon dogs everywhere. All viruses, whether they infect plants, animals or bacteria, are utterly dependent on living host [...]