Evolutionary diversification of TTX-resistant sodium channels in a predator-prey interaction
Evolutionary diversification of TTX-resistant sodium channels in a predator-prey interaction
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DOI：
10.1038/nature03444
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发表时间：
2005-04-07
期刊：
影响因子：
64.8
通讯作者：
Ruben, PC
中科院分区：
文献类型：
--
作者：
Geffeney, SL;Fujimoto, E;Ruben, PC
了解适应的分子遗传基础，提供了无与伦比的深入了解进化多样化发生的遗传机制。不同谱系中共同性状的进化是否是通过相似或独特的突变进行的，以及表型进化在多大程度上是由基因调控而不是基因功能的变化控制的，这些都是进化生物学中的基本问题，需要对遗传机制有这样的理解（1-3）。在这里，我们确定了在蛇骨骼肌中表达的钠通道tsNa（V）1.4的分子结构的新变化，这是与毒性蝾螈共同进化的束带蛇种群中河豚毒素（TTX）抗性差异的原因（4）。通过tsNa（V）1.4的功能表达，我们展示了通道氨基酸序列的差异如何影响TTX结合，并在四个蛇种群中赋予不同水平的抗性。这些结果表明，一种生理性状的进化是通过一系列在脊椎动物中高度保守的基因的独特功能变化而发生的。
Understanding the molecular genetic basis of adaptations provides incomparable insight into the genetic mechanisms by which evolutionary diversification takes place. Whether the evolution of common traits in different lineages proceeds by similar or unique mutations, and the degree to which phenotypic evolution is controlled by changes in gene regulation as opposed to gene function, are fundamental questions in evolutionary biology that require such an understanding of genetic mechanisms(1-3). Here we identify novel changes in the molecular structure of a sodium channel expressed in snake skeletal muscle, tsNa(V)1.4, that are responsible for differences in tetrodotoxin (TTX) resistance among garter snake populations coevolving with toxic newts(4). By the functional expression of tsNa(V)1.4, we show how differences in the amino-acid sequence of the channel affect TTX binding and impart different levels of resistance in four snake populations. These results indicate that the evolution of a physiological trait has occurred through a series of unique functional changes in a gene that is otherwise highly conserved among vertebrates.