Independent Evolutionary Origins of Tetrodotoxin Resistance as a Test of the Geographic Mosaic of Coevolution

捕食者和猎物之间军备竞赛的共同进化的证据将在有毒蝾螈和它们抵抗蛇的捕食者之间独特的自然相互作用中得到评估。蝾螈拥有一种神经毒素河豚毒素(TTX)，它可以阻断神经和肌肉中的钠通道。已知的捕食者中没有一种能够摄取TTX并存活下来，除了索姆诺菲斯属的吊袜蛇。以前的工作表明，捕食者和猎物具有相当程度的防御和开发能力，但Newt毒素的来源尚不清楚。高效液相色谱将被用来分析实验室饲养和饲养的蝾螈体内的毒素水平，以确定是否存在必要的个体、遗传和种群变异，以进化对捕食者的反应，从而评估观察到的匹配模式是否与共同进化的军备竞赛观点一致。了解推动进化的物种之间的相互作用是进化生物学的一个主要目标。共同进化是指一个物种因应另一个物种而进化，被认为是生物多样性的主要引擎之一。虽然协同进化被认为是许多生态相互作用的共同结果，但有大量的理论和经验理由怀疑捕食者和猎物的相互作用可能是不同的。这项研究将通过确定两栖动物中TTX的来源，减轻一种重要的神经毒素TTX的自然变异。TTX广泛用于神经功能和发育的研究。

Evidence for arms-race coevolution between predator and prey will beevaluated in a unique natural interaction between toxic newts and theirresistant snake predators. Newts possess the neurotoxin tetrodotoxin(TTX), which blocks sodium channels in nerves and muscles. No knownpredator can ingest TTX and survive except for garter snakes of thegenus Thamnophis. Previous work demonstrated that predator and prey havematched levels of defensive and exploitative abilities, but the sourceof newt toxicity is still unknown. High Performance LiquidChromatography (HPLC) will be used to assay levels of toxin inlaboratory bred and reared newts to determine whether the requisiteindividual, genetic and population variation exists for newts to evolvein response to predators, allowing an evaluation of whether observedpatterns of matching are consistent with an arms race view ofcoevolution. Understanding the interactions between species that drivecoevolution is a major goal of evolutionary biology. Coevolution, inwhich one species evolves in response to another species, is thought tobe one of the major engines of biodiversity. Although coevolution isthought to be a common outcome of many ecological interaction, there arestrong theoretical and empirical reasons to suspect that predator-preyinteractions might be different. This research will shed important lighton natural variation in an important neurotoxin, TTX, which is usedwidely in studies of nerve function and development, by identifying thesources of TTX in amphibians.