Hybridization has the potential to generate or homogenize biodiversity and is a particularly common phenomenon in plants, with an estimated 25% of plant species undergoing interspecific gene flow. However, hybridization in Amazonia's megadiverse tree flora was assumed to be extremely rare despite extensive sympatry between closely related species, and its role in diversification remains enigmatic because it has not yet been examined empirically. Using members of a dominant Amazonian tree family (Brownea, Fabaceae) as a model to address this knowledge gap, our study recovered extensive evidence of hybridization among multiple lineages across phylogenetic scales. More specifically, using targeted sequence capture our results uncovered several historical introgression events between Brownea lineages and indicated that gene tree incongruence in Brownea is best explained by reticulation, rather than solely by incomplete lineage sorting. Furthermore, investigation of recent hybridization using ~19,000 ddRAD loci recovered a high degree of shared variation between two Brownea species that co‐occur in the Ecuadorian Amazon. Our analyses also showed that these sympatric lineages exhibit homogeneous rates of introgression among loci relative to the genome‐wide average, implying a lack of selection against hybrid genotypes and persistent hybridization. Our results demonstrate that gene flow between multiple Amazonian tree species has occurred across temporal scales, and contrasts with the prevailing view of hybridization's rarity in Amazonia. Overall, our results provide novel evidence that reticulate evolution influenced diversification in part of the Amazonian tree flora, which is the most diverse on Earth.

中文翻译：

---

跨进化尺度的渗入表明网状结构有助于亚马逊树的多样性。

杂交具有产生或均化生物多样性的潜力，并且是植物中特别普遍的现象，估计有25％的植物物种经历种间基因流动。然而，尽管在密切相关的物种之间有广泛的共生关系，但亚马逊亚马孙大树种植物群中的杂交被认为是极为罕见的，并且由于尚未进行实证研究，其在多样化中的作用仍然是个谜。通过使用占主导地位的亚马逊树木家族成员（布朗亚，豆科）的模型来解决这一知识鸿沟，我们的研究获得了广泛的证据，涵盖了跨系统发育尺度的多个谱系之间的杂交。之间。更具体，有针对性的使用顺序拍摄我们的研究结果发现了几个历史事件渗入Brownea并指出，布朗尼中的基因树不一致之处最好通过网状解释，而不是仅通过不完整的谱系排序来解释。此外，使用最近〜杂交的调查19000 ddRAD基因座回收两者之间的高度共享变异Brownea厄瓜多尔亚马逊地区共存的物种。我们的分析还表明，相对于全基因组平均水平，这些同胞谱系在基因座之间表现出均等的渗入速率，这意味着缺乏针对杂交基因型和持久杂交的选择。我们的结果表明，多个亚马逊树种之间的基因流已发生在各个时间尺度上，并且与杂交在亚马逊地区稀有性的普遍观点形成了鲜明对比。总体而言，我们的结果提供了新的证据，表明网状进化影响了部分亚马逊树植物群的多样性，而后者是地球上最多样化的。