Footprints of local adaptation span hundreds of linked genes in the Atlantic silverside genome

The study of local adaptation in the presence of ongoing gene flow is the study of natural selection in action, revealing the functional genetic diversity most relevant to contemporary pressures. In addition to individual genes, genome-wide architecture can itself evolve to enable adaptation. Distributed across a steep thermal gradient along the east coast of North America, Atlantic silversides (Menidia menidia) exhibit an extraordinary degree of local adaptation in a suite of traits, and the capacity for rapid adaptation from standing genetic variation, but we know little about the patterns of genomic variation across the species range that enable this remarkable adaptability. Here we use low-coverage, whole-transcriptome sequencing of Atlantic silversides sampled along an environmental cline to show marked signatures of divergent selection across a gradient of neutral differentiation. Atlantic silversides sampled across 1,371 km of the southern section of its distribution have very lo...针对存在持续基因流的本地适应展开研究，实则是解析正在运作的自然选择过程，可揭示与当代选择压力高度相关的功能遗传多样性。除单个功能基因外，全基因组架构本身亦可通过演化实现适应性进化。沿北美东海岸陡峭温度梯度分布的大西洋银汉鱼（Atlantic silversides，*Menidia menidia*），在一系列性状上展现出极高程度的本地适应能力，同时具备从现存遗传变异中快速适应的潜能，但目前学界对支撑其卓越适应性的物种分布范围内的基因组变异模式仍所知有限。本研究对沿环境梯度取样的大西洋银汉鱼开展低覆盖度全转录组测序，结果显示中性分化梯度下存在显著的歧化选择信号。沿该物种分布南部1371公里区间取样的大西洋银汉鱼，其极