A contagious and fatal cancer has been driving the population of the Tasmanian devil into extinction but findings of a new study have revealed that the endangered species are evolving in response to this threat.
The devil facial tumor disease (DFTD) is one of the only three known transmissible cancers in the world. It is so deadly that its fatality rate is nearly 100 percent. The disease has wiped out at least 80 percent of the devil's number in Tasmania, the only place where the animals live, since it was detected 20 years ago.
The disease easily spreads among Tasmanian devils because the Australian marsupials tend to show aggression by biting each other's face. Models have already predicted the extinction of the iconic animal but its population persisted at long-diseased sites.
Now, findings of a new study revealed that the Tasmanian devil, the largest carnivorous marsupial in the world, may have developed a natural mechanism that helps save their population from the rapid spread of DFTD.
Andrew Storfer, from Washington State University, and colleagues discovered changes in two regions in the genomes of the animals in response to DFTD.
The findings of the study, which were published in the journal Nature Communications on Aug. 30, suggest that some populations of the Tasmanian devil are evolving genetic resistance to the deadly cancer, which could help their species avoid extinction.
"Here we report rare genomic evidence of a rapid, parallel evolutionary response to strong selection imposed by a wildlife disease," the researchers wrote in their study. "DFTD spreads between hosts by suppressing and evading the immune system, and our results suggest that hosts are evolving immune-modulated resistance that could aid in species persistence in the face of this devastating disease."
The genomic data may likewise provide helpful information that could help future medical studies that investigate how animals go through evolutionary changes in response to pathogens.
Storfer noted that their research expresses a hope for the survival of the Tasmanian devil amid the prevalence of DFTD.
"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," Storfer said.
The researchers hope that the devils that appear to have DFTD-resistant DNA can be bred. Doing so can improve the genetic diversity of the species, which could prove helpful in case devil reintroduction would be deemed necessary in the future.
