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| Name | Widespread convergent evolution discovered in unlikely prey species |
| Video Uploader | Video From MDPI |
| Upload Date | This Video Uploaded At 01-08-2023 10:55:20 |
| Video Discription | A transformative arms race between predator and prey has occurred on a global scale, featuring an unexpected prey species - the legless amphibian known as caecilians. An international team of researchers discovered that caecilians in various different areas display snake venom resistance. This 'unprecedented' finding regarding prey species resistance provides a robust model for the fundamental evolutionary concept of predator-prey interactions, known as convergence evolution. In the study, published in the International Journal of Molecular Sciences (IJMS), the researchers observed that caecilians developed snake venom resistance in response to increasing predatory pressure from elapid snakes, such as cobras and coral snakes. These predator species are characterised by a new way of delivering venom via their hollow, fixed, syringe-like fangs. Associate Professor Bryan Fry from the University of Queensland (UQ) and author on the paper, describes how these amphibians evolved to keep up with their predators. Fry states, “our research provides a textbook example of how a single predatory pressure can trigger an evolutionary cascade where the same way of fighting back arises independently multiple times in a species’ different lineages”. In every predator-prey relationship, the species most at risk of predation face intense selective pressure to develop a defence mechanism. This defence can be mechanical, such as the ability to run fast, or chemical, like venom or poison. Caecilians, being part of venomous snakes' diet, found themselves under particularly heightened pressure to evolve resistance to snake venom. Dry Fry explains, “despite being quite slippery, caecilians are worm-like in their locomotion and speed and were incredibly easy prey to cobras and other snakes, which used their fangs to kill them and eat them later”. Without the selective pressure to evolve a form of defence, Dr Fry says, “it would have been absolute carnage to the point where elapids were basically grazing on caecilians, contributing to the rapid spread of elapid snakes across Africa, Asia, and the Americas”. “The caecilian’s ability to persevere and evolve despite these pressures is like a movie – like the survivors of Judgement Day fighting back by changing the chemical landscape.” The researchers studied caecilian species from across all known families across the globe, including those in the Seychelles islands, untouched by elapid snakes. Author on the paper, Marco Mancuso from Vrije Universiteit Brussel, says their study involved using tissue collections from 37 caecilian species to sequence a part of the neuromuscular receptor, bound by toxins in snake venom. “We showed that resistance to elapid snake venom neurotoxins has evolved on at least 15 times – which is absolutely without precedent,” says Mancuso. This included three times in Africa, seven times in the Americas, and five times in Asia. Mancuso highlights that the team's theory was confirmed by studying caecilians on Seychelles islands. These caecilians didn't have resistance to venom, which matches the fact that elapid snakes are not found there. “It’s an extraordinary signal for response to such severe selection pressure, where the survivors of the onslaught [of elapid snakes] were those who were a bit less sensitive to the venom and some had mutations that made them completely immune,” says Mancuso. How did caecilian species achieve this never-before-seen venom resistance? Dr Fry explains how they deployed three different kinds of biological methods to accomplish this feat. “One kind is putting up a form of barricade that blocks the ability of the toxins to reach receptors that would normally elicit a deadly reaction,” Fry explains. “A second form of resistance is changing the physical shape of the receptor. As the toxins have evolved to be like keys and insert into the lock-like receptor, changing the shape means the toxin no longer fits.” “Lastly, caecilians essentially deploy an electromagnetic ‘weapon’ which reverses the charge during this toxin-receptor interaction,” Fry says. While this discovery may not offer immediate benefits like new anti-venoms for humans, it emphasises the compelling impact of the evolutionary arms race between predator and prey, as the first documentation of this resistance pattern in amphibians. If you're interested in learning more about this research, you can access the paper published in the IJMS here: https://t.ly/rRMHF Qtezryg_I_g |
| Category | Science & Technology |
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