Certain snakes have evolved a unique genetic trick to avoid being eaten byvenomous snakes, according to University of Queensland research.
Associate Professor Bryan Fry from UQ’s Toxin Evolution Lab said the techniqueworked in a manner similar to the way two sides of a magnet repel each other.
“The target of snake venom neurotoxins is a strongly negatively charged nervereceptor,” Dr Fry said.
“This has caused neurotoxins to evolve with positively charged surfaces,thereby guiding them to the neurological target to produce paralysis.
“But some snakes have evolved to replace a negatively charged amino acid ontheir receptor with a positively charged one, meaning the neurotoxin isrepelled.
“It’s an inventive genetic mutation and it’s been completely missed until now.
“We’ve shown this trait has evolved at least 10 times in different species ofsnakes.”
The researchers found that the Burmese python – a slow-moving terrestrialspecies vulnerable to predation by cobras – is extremely neurotoxin resistant.
“Similarly, the South African mole snake, another slow-moving snake vulnerableto cobras, is also extremely resistant,” Dr Fry said.
“But Asian pythons which live in trees as babies, and Australian pythons whichdo not live alongside neurotoxic snake-eating snake, do not have thisresistance.
“We’ve long known that some species – like the mongoose – are resistant tosnake venom through a mutation that physically blocks neurotoxins by having abranch-like structure sticking out of the receptor, but this is the first timethe magnet-like effect has been observed.”
“It has also evolved in venomous snakes to be resistant to their ownneurotoxins on at least two occasions.”
The discovery was made after the establishment of UQ’s new $2 millionbiomolecular interaction facility, the Australian Biomolecular InteractionFacility (ABIF).
“There’s some incredible technology at the ABIF allowing us to screenthousands of samples a day,” Dr Fry said.
“That facility means we can do the kinds of tests that would have just beenscience fiction before, they would have been completely impossible.”
The research has been published in Proceedings of the Royal Society B (DOI:10.1098/rspb.2020.2703).
The Australian Biomolecular Interaction Facility (ABIF) was funded through a$1 million Australian Research Council Linkage Infrastructure, Equipment andFacilities (LIEF) grant, with $1 million contributing funding from UQ,Griffith University, Queensland University of Technology, James CookUniversity, and the University of Sunshine Coast.
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