Climate Change Brings Disease Threat for Polar Bears

With its habitats shrinking and food supplies dwindling, the fate of the polar bear looks grim in the face of climate change. Now comes news that the iconic Arctic mammal may face another potentially devastating threat: it may be particularly vulnerable to new pathogens moving northwards as a result of warming. Diana Weber, who works at both the New College of Florida, Sarasota, and the American Museum of Natural History in New York, led a team that sequenced DNA from 98 polar bears in Canada. They looked specifically for genes coding the major histocompatibility complex (MHC) – a molecule found on the surface of cells that acts as a crucial component of the immune systems of most vertebrates.