HOBART, Australia, Aug. 31 (UPI) -- For the last two decades, scientists have struggled to curtail the spread of a deadly and contagious cancer among Tasmanian devils. Finally, the have some good news. A new study suggests evolution may be helping the cause.
Since devil facial tumor disease was discovered 20 years ago, the cancer has killed roughly 80 percent of Tasmania's devil population. Researchers have a made some progress through the use of vaccines, but the island's population continues to decline.
Now, genomic analysis suggests the species is developing a genetic resistance to the disease.
"Our study suggests hope for the survival of the Tasmanian devil in the face of this devastating disease," Andrew Storfer, a professor of biology at Washington State University, said in a news release. "Ultimately, it may also help direct future research addressing important questions about the evolution of cancer transmissibility and what causes remission and reoccurrence in cancer and other diseases."
Despite the dramatic rate of decline among Tasmanian devils, groups of Tasmanian devils persist healthily at sites plagued by the disease. Storfer and his colleagues were first intrigued by the survivors.
"If a disease comes in and knocks out 90 percent of the individuals, you might predict the 10 percent who survive are somehow genetically different," said researcher Paul Hohenlohe, assistant professor of biology at the University of Idaho. "What we were looking for were the parts of the genome that show that difference."
Scientists compared gene frequency among DNA samples collected from devils at sites before and after the outbreak of devil facial tumor disease. Their analysis -- detailed in the journal Nature Communications -- revealed two small genomic regions where changes became common in the wake of the outbreak. Scientists linked five of the seven identified genes to cancer or immune function.
Researchers are now considering breeding Tasmanian devils with genetic immunity to the cancer.