Dept. of Biology, San Diego State University, San Diego, CA 92182, United States; Evolution, Ecology, and Organismal Biology Department, University of California Riverside, Riverside, CA 92521, United States.
Evolution, Ecology, and Organismal Biology Department, University of California Riverside, Riverside, CA 92521, United States.
Mol Phylogenet Evol. 2021 Aug;161:107165. doi: 10.1016/j.ympev.2021.107165. Epub 2021 Mar 30.
Introgressive hybridization can be a powerful force impacting patterns of evolution at multiple taxonomic levels. We aimed to understand how introgression has affected speciation and diversification within a species complex of jumping spiders. The Habronattus americanus subgroup is a recently radiating group of jumping spiders, with species now in contact after hypothesized periods of isolation during glaciation cycles of the Pleistocene. Effects of introgression on genomes and morphology were investigated using phylogenomic and clustering methods using RADseq, ultraconserved elements (UCEs), and morphological data. We characterized 14 unique species/morphs using non-metric multidimensional scaling of morphological data, a majority of which were not recovered as monophyletic in our phylogenomic analyses. Morphological clusters and genetic lineages are highly incongruent, such that geographic region was a greater predictor of phylogenetic relatedness and genomic similarity than species or morph identity. STRUCTURE analyses support this pattern, revealing clusters corresponding to larger geographic regions. A history of rapid radiation in combination with frequent introgression seems to have mostly homogenized the genomes of species in this system, while selective forces maintain distinct male morphologies. GEMMA analyses support this idea by identifying SNPs correlated with distinct male morphologies. Overall, we have uncovered a system at odds with a typical bifurcating evolutionary model, instead supporting one where closely related species evolve together connected through multiple introgression events, creating a reticulate evolutionary history.
渐渗杂交是一种强大的力量，可以影响多个分类学水平的进化模式。我们旨在了解渐渗杂交如何影响跳蛛物种复合体的物种形成和多样化。Habronattus americanus 亚组是一个新近辐射的跳蛛群体，在更新世冰期循环期间假设的隔离期后，现在已经接触到了物种。使用 RADseq、超保守元件 (UCE) 和形态数据的系统发育和聚类方法研究了渐渗杂交对基因组和形态的影响。我们使用形态数据的非度量多维标度对 14 个独特的物种/形态进行了特征描述，其中大多数在我们的系统发育分析中未被恢复为单系。形态聚类和遗传谱系高度不一致，以至于地理区域比物种或形态身份更能预测系统发育亲缘关系和基因组相似性。STRUCTURE 分析支持这种模式，揭示了与较大地理区域相对应的聚类。快速辐射的历史加上频繁的渐渗杂交似乎使该系统中的物种基因组大多同质化，而选择压力则维持了独特的雄性形态。GEMMA 分析通过识别与独特雄性形态相关的 SNP 来支持这一观点。总体而言，我们发现了一个与典型分支进化模型不一致的系统，而是支持一个通过多次渐渗事件连接的密切相关的物种共同进化的系统，从而创造了一个网状进化历史。
