Department of Biological Science, Florida State University, Tallahassee, FL.
Department of Scientific Computing, Florida State University, Tallahassee, FL.
Mol Biol Evol. 2017 Dec 1;34(12):3099-3110. doi: 10.1093/molbev/msx231.
A trait's genomic architecture can affect the rate and mechanism of adaptation, and although many ecologically-important traits are polygenic, most studies connecting genotype, phenotype, and fitness in natural populations have focused on traits with relatively simple genetic bases. To understand the genetic basis of polygenic adaptation, we must integrate genomics, phenotypic data, ecology, and fitness effects for a genetically tractable, polygenic trait; snake venoms provide such a system for studying polygenic adaptation because of their genetic tractability and vital ecological role in feeding and defense. We used a venom transcriptome-proteome map, quantitative proteomics, genomics, and fitness assays in sympatric prey to construct a genotype-phenotype-fitness map for the venoms of an island-mainland pair of rattlesnake populations. Reciprocal fitness experiments demonstrated that each population was locally adapted to sympatric prey. We identified significant expression differentiation with little to no coding-sequence variation across populations, demonstrating that expression differentiation was exclusively the genetic basis of polygenic adaptation. Previous research on the genetics of adaptation, however, has largely been biased toward investigating protein-coding regions because of the complexity of gene regulation. Our results showed that biases at the molecular level can be in the opposite direction, highlighting the need for more systematic comparisons of different molecular mechanisms underlying rapid, adaptive evolution in polygenic traits.
一个特征的基因组结构可以影响适应的速度和机制，尽管许多生态上重要的特征是多基因的，但大多数将基因型、表型和适应度联系起来的自然种群研究都集中在具有相对简单遗传基础的特征上。为了了解多基因适应的遗传基础，我们必须整合基因组学、表型数据、生态学和适应度效应，以研究具有遗传可操作性的多基因特征；蛇毒提供了这样一个研究多基因适应的系统，因为它们具有遗传可操作性，并且在进食和防御方面具有至关重要的生态作用。我们使用毒液转录组-蛋白质组图谱、定量蛋白质组学、基因组学和在同域猎物中的适应度测定，为一对响尾蛇种群的岛屿-大陆种群的毒液构建了基因型-表型-适应度图谱。相互适应度实验表明，每个种群都对同域猎物具有局部适应性。我们发现，尽管在种群之间存在很少的编码序列变异，但表达分化具有显著差异，这表明表达分化是多基因适应的唯一遗传基础。然而，以前关于适应遗传学的研究由于基因调控的复杂性而主要偏向于研究蛋白质编码区域。我们的结果表明，分子水平上的偏见可能方向相反，突出了需要对多基因特征中快速适应性进化的不同分子机制进行更系统的比较。
