Studies of convergence in wild populations have been instrumental in understanding adaptation by providing strong evidence for natural selection. At the genetic level, we are beginning to appreciate that the re-use of the same genes in adaptation occurs through different mechanisms and can be constrained by underlying trait architectures and demographic characteristics of natural populations. Here, we explore these processes in naturally adapted high- (HP) and low-predation (LP) populations of the Trinidadian guppy, Poecilia reticulata. As a model for phenotypic change this system provided some of the earliest evidence of rapid and repeatable evolution in vertebrates; the genetic basis of which has yet to be studied at the whole-genome level. We collected whole-genome sequencing data from ten populations (176 individuals) representing five independent HP-LP river pairs across the three main drainages in Northern Trinidad. We evaluate population structure, uncovering several LP bottlenecks and variable between-river introgression that can lead to constraints on the sharing of adaptive variation between populations. Consequently, we found limited selection on common genes or loci across all drainages. Using a pathway type analysis, however, we find evidence of repeated selection on different genes involved in cadherin signalling. Finally, we found a large repeatedly selected haplotype on chromosome 20 in three rivers from the same drainage. Taken together, despite limited sharing of adaptive variation among rivers, we found evidence of convergent evolution associated with HP-LP environments in pathways across divergent drainages and at a previously unreported candidate haplotype within a drainage.

中文翻译：

---

祖先变异的排水结构和常见的功能路径形状限制了天然高捕食和低捕食孔雀鱼的基因组收敛

通过为自然选择提供有力的证据，对野生种群趋同的研究有助于理解适应性。在遗传水平上，我们开始认识到，相同基因在适应中的重复利用是通过不同的机制发生的，并且可能受到自然种群的基本特征结构和人口统计学特征的限制。在这里，我们在特立尼达孔雀鱼（Poecilia reticulata）的自然适应的高（HP）和低捕食（LP）种群中探索这些过程。作为表型变化的模型，该系统提供了脊椎动物快速和可重复进化的一些早期证据。其遗传基础尚未在全基因组水平上进行研究。我们从特立尼达北部三个主要流域的五个独立的HP-LP河对的十个种群（176个个体）收集了全基因组测序数据。我们评估了种群结构，发现了几个LP瓶颈和河流之间的渗入变量，这些变量可能导致限制种群间适应性变异的共享。因此，我们发现所有引流物对共同基因或基因座的选择有限。但是，使用途径类型分析，我们发现在钙黏着蛋白信号传导中涉及的不同基因上反复选择的证据。最后，我们在来自同一排水系统的三条河流中的20号染色体上发现了一个大型重复选择的单倍型。综上所述，尽管河流之间自适应变化的共享有限，