Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, 4072, Australia.
Biol Rev Camb Philos Soc. 2022 Oct;97(5):1823-1843. doi: 10.1111/brv.12865. Epub 2022 May 17.
Convergence is the phenomenon whereby similar phenotypes evolve independently in different lineages. One example is resistance to toxins in animals. Toxins have evolved many times throughout the tree of life. They disrupt molecular and physiological pathways in target species, thereby incapacitating prey or deterring a predator. In response, molecular resistance has evolved in many species exposed to toxins to counteract their harmful effects. Here, we review current knowledge on the convergence of toxin resistance using examples from a wide range of toxin families. We explore the evolutionary processes and molecular adaptations driving toxin resistance. However, resistance adaptations may carry a fitness cost if they disrupt the normal physiology of the resistant animal. Therefore, there is a trade-off between maintaining a functional molecular target and reducing toxin susceptibility. There are relatively few solutions that satisfy this trade-off. As a result, we see a small set of molecular adaptations appearing repeatedly in diverse animal lineages, a phenomenon that is consistent with models of deterministic evolution. Convergence may also explain what has been called 'autoresistance'. This is often thought to have evolved for self-protection, but we argue instead that it may be a consequence of poisonous animals feeding on toxic prey. Toxin resistance provides a unique and compelling model system for studying the interplay between trophic interactions, selection pressures and the molecular mechanisms underlying evolutionary novelties.
趋同进化是指不同谱系中独立进化出相似表型的现象。一个例子是动物对毒素的抗性。毒素在生命之树上已经进化了很多次。它们会破坏目标物种的分子和生理途径，从而使猎物失去能力或阻止捕食者。作为回应，许多暴露于毒素的物种进化出了分子抗性，以抵消其有害影响。在这里，我们使用来自广泛毒素家族的例子，回顾了关于毒素抗性趋同进化的现有知识。我们探讨了驱动毒素抗性的进化过程和分子适应。然而，如果抗性适应会破坏抗性动物的正常生理机能，它们可能会带来适应度成本。因此，在维持功能分子靶标和降低毒素敏感性之间存在权衡。很少有解决方案能够满足这种权衡。因此，我们看到一系列相对较少的分子适应在不同的动物谱系中反复出现，这一现象与确定性进化模型一致。趋同进化也可能解释了所谓的“自动抗性”。这通常被认为是为了自我保护而进化的，但我们认为，它可能是有毒动物以有毒猎物为食的结果。毒素抗性为研究营养相互作用、选择压力以及进化新奇的分子机制之间的相互作用提供了一个独特而引人注目的模型系统。
