Widespread reticulate evolution in an adaptive radiation
Widespread reticulate evolution in an adaptive radiation
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适应性辐射中广泛的网状进化
DOI：
10.1093/evolut/qpad011
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发表时间：
2023
期刊：
影响因子：
3.3
通讯作者：
Burbrink, Frank T.
中科院分区：
文献类型：
--
作者：
DeBaun, Dylan;Rabibisoa, Nirhy;Raselimanana, Achille P.;Raxworthy, Christopher J.;Burbrink, Frank T.
进化生物学的一个基本假设是系统发育遵循分叉过程。然而，混合物种形成和基因渗入在许多群体中得到越来越广泛的记录。混合推理研究历来仅限于小类群，而对深时间尺度网状结构的普遍性和趋势的探索仍未得到探索。我们研究了马达加斯加 109 种宝石蛇（Pseudoxyrhophiinae）的适应性辐射进化史，以确定基因渗入的潜在实例。使用多种网络推理方法，我们在宝石蛇 2200 万年的进化史上发现了 12 个网状事件，产生了该群体 28% 的多样性，其中一个网状事件导致了 18 个物种辐射的多样化。这些网状结构存在于基因树高度不一致的节点处，并且发生在沿着南北轴分布且具有相似生态的亲本谱系中。较年轻的杂交体占据了亲本谱系之间的中间接触区，这表明该群体中的物种形成后扩散并未侵蚀基因渗入的空间特征。尽管更新世期间整体物种形成率下降，但随着时间的推移，网状结构不断积累。这表明，虽然由于物种积累和环境变化，分叉物种形成率可能会下降，但杂交形成的物种可能对这些过程更加稳健。
A fundamental assumption of evolutionary biology is that phylogeny follows a bifurcating process. However, hybrid speciation and introgression are becoming more widely documented in many groups. Hybrid inference studies have been historically limited to small sets of taxa, while exploration of the prevalence and trends of reticulation at deep time scales remains unexplored. We study the evolutionary history of an adaptive radiation of 109 gemsnakes in Madagascar (Pseudoxyrhophiinae) to identify potential instances of introgression. Using several network inference methods, we find 12 reticulation events within the 22-million-year evolutionary history of gemsnakes, producing 28% of the diversity for the group, including one reticulation that resulted in the diversification of an 18 species radiation. These reticulations are found at nodes with high gene tree discordance and occurred among parental lineages distributed along a north-south axis that share similar ecologies. Younger hybrids occupy intermediate contact zones between the parent lineages showing that post-speciation dispersal in this group has not eroded the spatial signatures of introgression. Reticulations accumulated consistently over time, despite drops in overall speciation rates during the Pleistocene. This suggests that while bifurcating speciation rates may decline as the result of species accumulation and environmental change, speciation by hybridization may be more robust to these processes.