SYDNEY, March 14 (Xinhua) -- A unique genetic adaptation in koalas north of the Brisbane River in Australia was offering new hope for the species' survival, according to a new discovery.
Some koalas in the Sunshine Coast hinterland have evolved a genetic switch that suppresses the koala retrovirus, which weakens their immune system and makes them vulnerable to diseases like chlamydia and lymphoma, said the study published in Cell on Friday.
The genetic switch effectively reduces the impact of the retrovirus, strengthening the immune system of the beloved but endangered marsupial, said Keith Chappell, a virologist at the University of Queensland (UQ)'s Australian Institute of Bioengineering and Nanotechnology.
The new finding could be instrumental in breeding programs aimed at producing more resilient populations.
About 30 percent of the local koala population in the Sunshine Coast hinterland carry this genetic adaptation, whereas the unique immunity is nearly absent in populations on the Gold Coast in Australia's Queensland, Chappell said.
Infections such as chlamydia have severely impacted koala populations in Queensland and New South Wales. Additionally, the virus has been associated with lymphomas, leading to the deaths of many koalas in captivity, the study said.
The research, led by Michaela Blyton from UQ, highlighted how this "adaptive genomic immunity" is being inherited and could be leveraged to help other populations, particularly in regions where koalas have been devastated by disease. However, the spread of this adaptation through natural evolution would take many generations.
"Out of all the species on the planet, this is the only one where we can see a genetic response to a retrovirus in real time, rather than looking at responses to things that got into the genome millions of years ago," Chappell said.
The virologist added the koala retrovirus only entered the marsupial's genome in the past few thousand years, which is really recent in evolutionary terms.
William Theurkauf from the University of Massachusetts, an expert in genome evolution, saw parallels with his research on fruit flies and collaborated with the UQ team to analyze the phenomenon. ■
