Experimental evidence of genome-wide impact of ecological selection during early stages of speciation-with-gene-flow

Theory predicts that speciation-with-gene-flow is more likely when the consequences of selection for population divergence transitions from mainly direct effects of selection acting on individual genes to a collective property of all selected genes in the genome. Thus, understanding the direct impacts of ecologically based selection, as well as the indirect effects due to correlations among loci, is critical to understanding speciation. Here, we measure the genome-wide impacts of host-associated selection between hawthorn and apple host races of Rhagoletis pomonella (Diptera: Tephritidae), a model for contemporary speciation-with-gene-flow. Allele frequency shifts of 32 455 SNPs induced in a selection experiment based on host phenology were genome wide and highly concordant with genetic divergence between co-occurring apple and hawthorn flies in nature. This striking genome-wide similarity between experimental and natural populations of R. pomonella underscores the importance of ecologi...理论预测，当驱动种群分化的选择效应从主要作用于单个基因的直接选择效应，转变为基因组中所有受选基因的集体属性时，存在基因流的物种形成（speciation-with-gene-flow）更易发生。因此，解析生态选择的直接效应，以及基因座间连锁关联所带来的间接效应，对于理解物种形成过程至关重要。本研究以作为当代存在基因流的物种形成研究模型的苹果实蝇（Rhagoletis pomonella，双翅目：实蝇科）为对象，测定其山楂寄主型与苹果寄主型之间的寄主关联选择的全基因组效应。在基于寄主物候的选择实验中，诱导产生的32455个单核苷酸多态性（Single Nucleotide Polymorphism）位点的等位基因频率偏移遍及全基因组，且与自然界中同域共存的苹果寄主型与山楂寄主型实蝇之间的遗传分化高度契合。这一实验种群与自然种群间显著的全基因组相似性，凸显了生态选择在