Data from: Gene flow among Modoc sucker and Sacramento sucker populations in the upper Pit River

The Modoc sucker (Catostomus microps) is a species that received legal protection in the United States based partially on concerns that anthropogenic environmental changes had restricted migration among populations and catalyzed hybridization with a congener, the Sacramento sucker (C. occidentalis). We applied eight microsatellite markers to samples of both species collected from throughout the range of Modoc suckers: two tributaries in the Pit River sub-basin and one tributary in the Goose Lake sub-basin. Modoc sucker populations in these three tributaries appeared to be largely isolated from one another: migration among Pit River tributaries appeared no greater than migration among sub-basins. Sacramento sucker populations appeared relatively more connected with one another, especially within the sub-basins. Interspecific hybrids were detected in all three tributaries. Tributaries in the Pit River sub-basin, which have retained typical habitats for both species, yielded relatively low proportions of hybrids (1.6% - 2.3%). The tributary in the Goose Lake sub-basin, which has undergone multiple cycles of hydrological change over the past two centuries, yielded a higher proportion of hybrids (10.9%). We conclude that hybridization between Modoc suckers and Sacramento suckers is not an active threat, but may be of conservation concern in situations where the habitat of one or both of these species has been eliminated or modified.

莫多克吸口鲶（Catostomus microps）是一种在美国获得法定保护的物种，其受保护的部分原因在于人为环境变化限制了种群间的迁移，并促使其与同属近缘物种萨克拉门托吸口鲶（C. occidentalis）发生杂交。我们采用8个微卫星标记，对采集自莫多克吸口鲶整个分布范围内的两个物种的样本进行了分析，样本分别来自皮特大河子流域的两条支流以及鹅湖子流域的一条支流。这三条支流中的莫多克吸口鲶种群彼此间基本处于隔离状态：皮特大河各支流间的迁移程度并不高于跨子流域间的迁移。萨克拉门托吸口鲶种群的连通性相对更强，尤其是在同一子流域内部。我们在三条支流中均检测到了种间杂交个体。皮特大河子流域的支流保留了适配两个物种的典型栖息地，其杂交个体比例相对较低（1.6% - 2.3%）。而经历过过去两个世纪多次水文变化循环的鹅湖子流域支流，其杂交个体比例更高（10.9%）。本研究得出结论：莫多克吸口鲶与萨克拉门托吸口鲶之间的杂交并非当前的活跃威胁，但在其中一个或两个物种的栖息地遭到破坏或改造的情况下，该现象仍可能引发保护层面的担忧。