6 days ago
How Australian skinks developed immunity to deadly snake venom: Breakthrough research may transform antivenom science
Synopsis
University of Queensland researchers discovered that Australian skinks evolved molecular defenses against snake venom through mutations in their nicotinic acetylcholine receptor. These mutations, found independently across skink species, prevent venom from binding, ensuring survival. This convergent evolution, also seen in honey badgers and mongooses, offers insights for developing novel antivenoms and understanding evolutionary adaptations to venomous predators.
Australian skinks may have developed immunity to deadly snake venom In a groundbreaking study led by the University of Queensland (UQ), scientists have uncovered how Australian skinks such as the Major Skink ( Bellatorias frerei ) have evolved remarkable molecular defenses that shield them from even the most potent snake venoms—a discovery with sweeping implications for medicine and evolutionary found 25 independent mutations in the skinks' nicotinic acetylcholine receptor, a crucial muscle site that venom neurotoxins typically target to paralyze prey. These mutations block venom from attaching, thus maintaining nerve-muscle communication and survival—transforming what would be a fatal bite for most animals into a survivable encounter for skinks.
'Australian skinks have evolved tiny changes in a critical muscle receptor, called the nicotinic acetylcholine receptor. This receptor is normally the target of neurotoxins which bind to it and block nerve-muscle communication causing rapid paralysis and death. But in a stunning example of a natural counterpunch, we found that on 25 occasions skinks independently developed mutations at that binding site to block venom from attaching,' said Professor Bryan Fry, lead author and UQ zoologist. Some mutations add sugar molecules to the receptor, physically blocking toxins. Others substitute specific amino acids—most notably arginine at position 187—creating a resistant muscle site. These adaptations were validated through experiments simulating venom attacks; in some cases, the modified receptors didn't respond to venom at study astonishingly revealed that the Major Skink shares the same mutation found in honey badgers, famous for their resistance to cobra venom, and in mongooses that prey on venomous snakes. This recurring molecular defense across distant species shows the immense evolutionary pressure exerted by snake venom and highlights 'convergent evolution'—nature repeatedly finds the same solution to the same lethal problem.
The implications of these findings are profound. By understanding exactly how skinks neutralize venom, scientists may develop novel antivenoms and therapies for neurotoxic snakebites in humans. First author Dr. Uthpala Chandrasekara, who led laboratory tests, noted:
'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.' This evolutionary battle traces back millions of years to when venomous elapid snakes colonized Australia. Skinks, once defenseless, were driven to evolve resistance—sometimes repeatedly, in separate lineages. Scientists estimate that 27.5% of hundreds of studied skinks show elements of this resistance, contributing to the species' success in predator-rich environments.
The research, carried out in collaboration with museums across Australia and published in the International Journal of Molecular Sciences , equips scientists with insight into natural 'venom-proofing.'
