Recent lineage diversification in a venomous snake through dispersal across the Amazon River

Identifying the evolutionary and ecological mechanisms that drive lineage diversification in the species-rich tropics is of broad interest to evolutionary biologists. Here, we use phylogeographic and demographic analyses of genomic scale RADseq data to assess the impact of a large geographic feature, the Amazon River, on lineage formation in a venomous pitviper, Bothrops atrox. We compared genetic differentiation in samples from four sites near Santarem, Brazil that spanned the Amazon and represented major habitat types. A species delimitation analysis identified each population as a distinct evolutionary lineage while a species tree analysis with populations as taxa revealed a phylogenetic tree consistent with dispersal across the Amazon from north to south. Phylogenetic analyses of mtDNA variation confirmed this pattern and suggest that all lineages originated during the mid- to late-Pleistocene. Historical demographic analyses support a population model of lineage formation through...

识别驱动物种丰富的热带地区谱系分化（lineage diversification）的进化和生态机制，是进化生物学家广泛关注的课题。在此，我们利用基因组尺度RADseq数据的系统地理学（phylogeographic）和种群统计分析（demographic analysis），评估大型地理特征——亚马逊河——对剧毒响尾蛇Bothrops atrox谱系形成（lineage formation）的影响。我们比较了巴西圣塔伦附近四个位点样本的遗传分化（genetic differentiation），这些位点横跨亚马逊河并代表主要栖息地类型。物种界定分析（species delimitation analysis）将每个种群识别为独特的进化谱系（evolutionary lineage），而以种群为分类单元（taxa）的物种树分析（species tree analysis）揭示了一个与从北向南跨亚马逊河扩散（dispersal）一致的系统发育树（phylogenetic tree）。线粒体DNA（mtDNA）变异的系统发育分析证实了这一模式，并表明所有谱系起源于中晚更新世（mid- to late-Pleistocene）。历史种群统计分析（historical demographic analysis）支持通过……形成谱系的种群模型。