Devil wipeout? In Tasmania, that's the fear

Tasmanian devils are dying of a mysterious facial-tumor disease, and scientists are mightily perplexed. "In Tasmania, the Devil Now Faces Its Own Hell" is a New York Times article that examines this strange phenomenon, and what Australian scientists are doing. They're setting up a quarantine program for young devils that show no signs of the disease, to see if they can rescue the population--provided that the quarantined youngsters are disease-free. This disease looks similar to one in dogs, except that dogs just develop antibodies to the virus and don't develop symptoms. In Tasmanian devils, however, it's 100% fatal.

A little genetic diversity would help the devil population, however. As correspondent Sandra Blakeslee writes,

In this hypothesis, tumor cells alone are the infectious agent. In nature, this is not supposed to happen, Dr. Pyecroft conceded. Healthy animals exposed to pathogens, including tumor cells, will normally mount an immune response to fight off the infection.

But genetically speaking, devils are virtual clones. With scant variation in their DNA -- perhaps from a population bottleneck in the recent past -- they may have nearly identical immune systems. Hence they cannot fight off the tumor cells.

Every tumor cell examined so far is the same in every animal, male and female, regardless of area of origin. The chromosomal rearrangements, presumably from the one random mutation, are identical.

Wow.