For the first time, scientists have sequenced the complete genome of one of Australia's most iconic and endangered frogs – the Southern Corroboree Frog (Pseudophryne corroboree).
The Australian amphibian species is considered 'functionally extinct' due to chytridiomycosis, an infectious disease caused by the chytrid fungus. There are no viable wild populations, and the species are only able to survive with the support of zoos.
University of Melbourne researchers now hope to use the genome, which acts as an organism's genetic blueprint and set of DNA instructions, to help return the species to its natural habitat in the New South Wales (NSW) Snowy Mountains.
Published today in Wellcome Open Research, lead author University of Melbourne Dr Tiffany Kosch said the research has taken almost a decade and is one of the highest-quality frog genomes ever produced.
"This is the first time the genome of this species has been sequenced, and it was not easy due to its enormous size. We discovered that Southern Corroboree Frogs have remarkably large genomes—more than three times the size of the human genome," Dr Kosch said.
"Interestingly, we also found that more than 80 per cent of its genome is made up of non-coding DNA—genetic material that doesn't directly code for proteins. We're still exploring what this might mean for the species, and for other amphibians."
The researchers teamed up with the world's leading experts in genome sequencing, the Vertebrate Genomes Project at Rockefeller University, USA and the NSW Department of Climate Change, Energy, the Environment and Water to complete the work.
To map the genome, various tissues – including kidney and liver – were sampled from a male frog bred in captivity.
"Sadly, the survival of Southern Corroboree Frogs depends solely on conservation breeding programs such as those run at Melbourne Zoo, Healesville Sanctuary, and Taronga Conservation Society," Dr Kosch said.
"Mapping the genome is the critical first step in our ultimate goal to restore this unique and visually striking species to its natural place in the ecosystem. The genome allows us to understand which genes increase or decrease susceptibility to the chytrid disease.
"Our focus now turns to using what we have learned to selectively breed frogs that are resistant to chytrid fungus and able to not only survive but thrive naturally in the environment, without ongoing human intervention."
Mapping the Southern Corroboree Frog genome also has implications for conservation strategies for other amphibians threatened by chytridiomycosis.
"We plan to compare the genome with those of other amphibians to uncover broader patterns of resilience and improve the viability of other at-risk species," Dr Kosch said.
