A mysterious cancer epidemic that is wiping out populations of the Tasmanian devil is largely the result of low genetic diversity caused by human interference, according to a new study. Using genetic sequencing,
researchers determined that devils found on opposite ends of the Australian island state of Tasmania — which, consequently, should have been genetically distinct — were remarkably similar. Further analysis of 175 devils and museum specimens indicated that the species has had a low genetic diversity over the last century, making it vulnerable to disease, including a facial tumor epidemic transmitted by physical contact that has wiped out about 66 percent of the animals since it was first observed in 1996. “Devils are essentially immunological clones, so tumors pass between them without triggering an immune response,” said Katherine Belov, an associate professor of animal genetics at the University of Sydney, Australia. Populations of the devil on mainland Australia were wiped out by dingoes introduced by settlers, while on Tasmania humans hunted the marsupials as pests. The findings are published in the journal Proceedings of the National Academy of Sciences.