Genomic regions repeatedly involved in divergence among plant-specialized pea aphid biotypes

Understanding the genetic bases of biological diversification is a long-standing goal in evolutionary biology. Here we investigate whether replicated cases of adaptive divergence involve the same genomic regions in the pea aphid, Acyrthosiphon pisum, a large complex of genetically differentiated biotypes, each specialized on different species of legumes. A previous study identified genomic regions putatively involved in host-plant adaptation and/or reproductive isolation by performing a hierarchical genome scan in three biotypes. This led to the identification of 11 FST outliers among 390 polymorphic microsatellite markers. In this study, the outlier status of these 11 loci was assessed in eight biotypes specialized on other host plants. Four of the 11 previously identified outliers showed greater genetic differentiation among these additional biotypes than expected under the null hypothesis of neutral evolution (α&lt;0.01). Whether these hotspots of genomic divergence result from adapt...解析生物多样化的遗传基础，是进化生物学领域长期以来的核心研究目标之一。本研究以豌豆蚜（*Acyrthosiphon pisum*）为研究对象——该类群由多个遗传分化显著的生物型（biotype）构成，每个生物型均专性寄生不同的豆科植物物种——旨在探究：在重复出现的适应性分化案例中，是否会共享相同的基因组区域。 此前一项研究通过对3个豌豆蚜生物型开展分层基因组扫描（hierarchical genome scan），鉴定出了若干可能与寄主植物适应性及/或生殖隔离相关的基因组区域；该研究在390个多态性微卫星标记（microsatellite marker）中，共筛选得到11个FST离群位点（FST outlier）。 本研究针对另外8种专性寄生不同寄主植物的生物型，对上述11个位点的离群位点属性进行了验证。结果显示，此前鉴定出的11个离群位点中，有4个在新增生物型间呈现出的遗传分化程度，显著高于中性进化（neutral evolution）零假设（null hypothesis）下的预期值（α<0.01）。 这些基因组分化热点是否由适应性演化所引发……