Phylogenetically diverse diets favor more complex venoms in North American pitvipers
Phylogenetically diverse diets favor more complex venoms in North American pitvipers
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DOI：
10.1073/pnas.2015579118
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发表时间：
2021-04-27
影响因子：
11.1
通讯作者：
Parkinson, Christopher L.
中科院分区：
文献类型：
--
作者：
Holding, Matthew L.;Strickland, Jason L.;Parkinson, Christopher L.
自然选择在性状复杂性进化中的作用可以通过测试复杂形式与其跨物种功能之间的假设联系来表征。捕食性毒液是由多种蛋白质组成的，这些蛋白质共同发挥作用，使猎物丧失能力。毒液的复杂性随着进化的时间尺度而波动，复杂性有明显的增加和减少，但这种变化的原因尚不清楚。我们测试了另一种假设，将毒液的复杂性与北美最大的前牙毒蛇--响尾蛇、铜斑蛇、悬铃蛇和棉嘴蛇--的食物选择生态来源联系起来。我们生成了毒液复杂性的独立转录组和蛋白质组学测量方法，并整理了几项自然历史研究以量化饮食变化。然后，我们构建了这些蛇的基因组规模的系统发育图，用于比较分析。引人注目的是，猎物的系统发育多样性与毒液的复杂性的相关性比猎物物种的整体多样性更强，特别是与猎物物种有关？在复杂性的进化中，分歧，而不仅仅是谱系的数量。Prey系统发育多样性进一步预测了蛇毒四个最大基因家族中的三个基因家族的转录复杂性，表明复杂性进化是许多独立基因家族之间的协同反应。我们认为，猎物的系统发育多样性衡量了毒液靶标在功能上的相关差异，这一说法得到了毒液凝固级联靶标的序列多样性的支持。我们的结果支持这样一个普遍的概念，即在决定捕食者特征复杂性的进化模式时，生态群落中物种的多样性比它们的总数更重要。
The role of natural selection in the evolution of trait complexity can be characterized by testing hypothesized links between complex forms and their functions across species. Predatory venoms are composed of multiple proteins that collectively function to incapacitate prey. Venom complexity fluctuates over evolutionary timescales, with apparent increases and decreases in complexity, and yet the causes of this variation are unclear. We tested alternative hypotheses linking venom complexity and ecological sources of selection from diet in the largest clade of front-fanged venomous snakes in North America: the rattlesnakes, copperheads, cantils, and cottonmouths. We generated independent transcriptomic and proteomic measures of venom complexity and collated several natural history studies to quantify dietary variation. We then constructed genome-scale phylogenies for these snakes for comparative analyses. Strikingly, prey phylogenetic diversity was more strongly correlated to venom complexity than was overall prey species diversity, specifically implicating prey species? divergence, rather than the number of lineages alone, in the evolution of complexity. Prey phylogenetic diversity further predicted transcriptomic complexity of three of the four largest gene families in viper venom, showing that complexity evolution is a concerted response among many independent gene families. We suggest that the phylogenetic diversity of prey measures functionally relevant divergence in the targets of venom, a claim supported by sequence diversity in the coagulation cascade targets of venom. Our results support the general concept that the diversity of species in an ecological community is more important than their overall number in determining evolutionary patterns in predator trait complexity.