The population genomics of repeated freshwater colonizations by Gulf Pipefish

How organisms adapt to the novel challenges imposed by the colonization of a new habitat has long been a central question in evolutionary biology. When multiple populations of the same species independently adapt to similar environmental challenges, the question becomes whether the populations have arrived at their adaptations through the same genetic mechanisms. In recent years, genetic techniques have been used to tackle these questions by investigating the genome‐level changes underlying local adaptation. Here, we present a genomic analysis of colonization of freshwater habitats by a primarily marine fish, the Gulf pipefish (Syngnathus scovelli). We sample pipefish from four geographically distinct freshwater locations and use double‐digest restriction site associated DNA sequencing to compare them to 12 previously studied saltwater populations. The two most geographically distant and isolated freshwater populations are the most genetically distinct, although demographic analysis sug...生物如何应对开拓新栖息地所带来的全新挑战，长期以来均为进化生物学领域的核心研究问题。当同一物种的多个种群独立适应相似的环境压力时，研究者的核心议题便转向：这些种群的适应性演化是否通过相同的遗传机制得以实现。近年来，研究者借助遗传技术，通过解析本地适应背后的基因组层面变化来解答上述问题。本研究针对一种主要营海洋栖息的鱼类——海湾尖嘴鱼（*Syngnathus scovelli*）的淡水栖息地开拓过程开展基因组分析。我们从4个地理上相互独立的淡水采样点采集海湾尖嘴鱼样本，并采用双酶切限制性位点关联DNA测序（double-digest restriction site associated DNA sequencing）技术，将其与此前已被研究的12个海水种群进行比对分析。尽管种群动态分析显示……但地理距离最远、隔离程度最高的两个淡水种群，其遗传分化程度也最为显著。