Australian skinks have evolved the means to resist snake venom by shutting down their muscles, suggests new research, which could help to inform future treatments for snakebites.
Research led by the University of Queensland has found that multiple species of Australian skink have evolved venom resistance through changes to a critical muscle receptor.
In other animals, the receptor is the target of venom neurotoxins, which cause rapid paralysis and death.
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A study co-author, Prof Bryan Fry, who leads UQ’s adaptive biotoxicology lab, said when venomous snakes arrived in Australia 25m to 30m years ago from Asia that skinks would have been their prey, resulting in evolutionary pressure to evolve venom resistance.
“What was fascinating was that with the kind of mutations that we documented in the Australian … skinks that gave rise to resistance are the kind of mutations that we’ve seen in other animals outside Australia,” Fry said. Mongooses, which feed on cobras, are one such example.
The researchers showed that the Australian major skink, Bellatorias frerei, had the same mutation that gave the honey badger its resistance to cobra venom.
The researchers looked at 47 skink species and found that 13 of these were resistant to snake venom.
Of these 13 species, some had multiple types of resistance, leading the researchers to discover that the skinks had developed independent mutations conferring resistance on 25 occasions.
Fry said the researchers had used tissue banks from museums across Australia rather than testing venom on live skinks.
A study co-author and UQ researcher, Dr Uthpala Chandrasekara, said: “We used synthetic peptides and receptor models to mimic what happens when venom enters an animal at the molecular level and the data was crystal clear, some of the modified receptors simply didn’t respond at all.”
“It’s fascinating to think that one tiny change in a protein can mean the difference between life and death when facing a highly venomous predator.
“The more we learn about how venom resistance works in nature, the more tools we have for the design of novel antivenoms.”
Dr Andrew Amey, collection manager of amphibians, reptiles and herpetology at Queensland Museum, who was not involved in the research, said there were more than 470 recognised species of Australian skink, with more being discovered all the time – with little known about them.
“It is great to see research looking into how they deal with such an important predator that just might tell us more about how we can manage the effects of snakebite ourselves,” Amey said.
The study was published in the International Journal of Molecular Sciences.
