Data from: Highly variable reproductive isolation among pairs of Catostomus species

Hybridization between diverged taxa tests the strength of reproductive isolation, and can therefore reveal mechanisms of reproductive isolation. However, it remains unclear how consistent reproductive isolation is across species’ ranges, and to what extent reproductive isolation might remain polymorphic as species diverge. To address these questions, we compared outcomes of hybridization across species pairs of Catostomus fishes in three rivers in the Upper Colorado River basin, where an introduced species, C. commersoni, hybridizes with at least two native species, C. discobolus and C. lattipinis. We observed substantial heterogeneity in outcomes of hybridization, both between species pairs and across geographically separate rivers within each species pair. We also observed hybridization of additional related species with our focal species, suggesting that reproductive isolation in this group involves interactions of multiple evolutionary and ecological factors. These findings suggest that a better understanding of the determinants of variation in reproductive isolation is needed, and that studies of reproductive isolation in hybrids should consider how the dynamics and mechanisms of reproductive isolation vary over ecological space and over evolutionary time. Our results also have implications for the conservation and management of native catostomids in the Colorado River basin. Heterogeneity in outcomes of hybridization suggests that the threat posed by hybridization and genetic introgression to the persistence of native species likely varies with extent of reproductive isolation, both across rivers and across species pairs.分化类群间的杂交可检测生殖隔离的强度，进而揭示其形成机制。然而目前仍不清楚，生殖隔离在物种分布范围内的一致性如何，以及随着物种分化，生殖隔离多态性的维持程度究竟几何。为解答上述问题，本研究对比了科罗拉多河上游流域三条河流中吸口鲤属（Catostomus）鱼类不同物种对的杂交结果：其中外来物种C. commersoni至少与两种本土物种——C. discobolus与C. lattipinis发生杂交。研究团队观察到，杂交结果存在显著异质性：既体现在不同物种对之间，也存在于同一物种对在地理分隔的不同河流之间。此外本研究还发现，其他近缘物种与本研究的目标物种亦存在杂交现象，这表明该类群的生殖隔离涉及多种演化与生态因子的相互作用。上述研究结果表明，我们亟需更深入地解析生殖隔离变异的决定因素，且针对杂交类群生殖隔离的研究，应当考虑生殖隔离的动态与机制如何随生态空间与演化时间发生变化。本研究结果同时对科罗拉多河流域本土吸口鲤科鱼类的保护与管理具有指导意义。杂交结果的异质性表明，杂交与遗传渐渗对本土物种存续构成的威胁程度，可能随不同河流、不同物种对间的生殖隔离强度差异而有所变化。