Tasmanian devils are evolving in response to a highly lethal and contagious form of cancer, according to an international team of researchers, which included scientists from Washington State University and the University of Idaho.
(Photo courtesy Washington State University, Storfer lab website)
WSU professor of biology Andrew Storfer and the team discovered that two regions in the genomes of Australia’s iconic marsupials are changing in response to the rapid spread of devil facial tumor disease (DFTD), a nearly 100% fatal and transmissible cancer first detected in 1996.
Over the past 20 years, tens of thousands of the world’s Tasmanian devils have died of the contagious cancer that spreads when the animals bite each other.
Tasmanian devils are the largest carnivorous marsupials in the world and an integral part of Australia’s natural heritage. Devils display significant aggression toward one another, which often involves biting on the face.
By comparison, canine transmissible venereal tumor, a sexually transmitted form of cancer that only affects dogs, has been around for at least 11,000 years and is generally not fatal to domesticated animals.
“Our study suggests hope for the survival of the Tasmanian devil in the face of this devastating disease,” Storfer said in a press release. “Ultimately, it may also help direct future research addressing important questions about the evolution of cancer transmissibility and what causes remission and re-occurrence in cancer and other diseases.”
Paul Hohenlohe, an assistant professor of biological sciences in the UI College of Science, contributed his expertise in searching for signs of evolutionary change across animal genomes, the full set of genes in an organism’s DNA.
“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,” Hohenlohe said in a press release. “What we were looking for was the parts of the genome that show that difference.”
The researchers mined a vast trove of devil DNA collected and stored before and after the outbreak of DFTD by wildlife ecologist and associate professor Menna Jones, study co-author, and her research team at the University of Tasmania.
Hohenlohe used technologies in UI’s Genomics Resource Core and Computational Resources Core to scan the genomes of nearly 300 individual animals, comparing close to a million snippets of DNA across each animal.
The scan found two pieces of the Tasmanian devil genome that showed signs of evolutionary change in response to the cancer and the force of natural selection it imposed.
“The results are exciting insomuch as they inform biology with regard to the potential for rapid evolutionary change in today’s dramatically changing world,” Storfer said. “Additionally, we are hopeful that our study may help with Tasmanian devil conservation efforts.”
The work was published in the Nature Communications (link below). It suggests some Tasmanian devil populations are evolving genetic resistance to DFTD that could help the species avoid extinction.
Posted September 2, 2016