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. latipinnis. 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 probably varies with extent of reproductive isolation, both across rivers and across species pairs.分化类群间的杂交可检验生殖隔离（reproductive isolation）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，也不清楚随着物种分化，生殖隔离在多大程度上会保持多态性。为解答上述问题，我们对科罗拉多河上游流域三条河流中的吸口鱼属（Catostomus）物种对的杂交结局开展了比较研究：该区域内的引进种C. commersoni可与至少两种本土物种C. discobolus及C. latipinnis发生杂交。我们观察到，杂交结局存在显著异质性：既体现在不同物种对之间，也存在于每个物种对所处的不同地理隔离河流中。同时我们还观察到，其他近缘物种与本研究关注的物种也存在杂交现象，这表明该类群的生殖隔离涉及多种进化与生态因子的相互作用。上述研究结果表明，我们亟需更深入地理解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考虑其动态性与机制如何随生态空间及进化时间发生变化。本研究结果对科罗拉多河流域本土吸口鱼的保护与管理亦具有参考意义。杂交结局的异质性表明，杂交与遗传渐渗（genetic introgression）对本土物种存续构成的威胁，可能随生殖隔离程度的不同而发生变化——这一差异既存在于不同河流之间，也存在于不同物种对之间。