Data from: Comparison of population genetic patterns in two widespread freshwater mussels with contrasting life histories in western North America

We investigate population genetic structuring in Margaritifera falcata, a freshwater mussel native to western North America, across the majority of its geographical range. We find shallow rangewide genetic structure, strong population-level structuring and very low population diversity in this species, using both mitochondrial sequence and nuclear microsatellite data. We contrast these patterns with previous findings in another freshwater mussel species group (Anodonta californiensis/A. nuttalliana) occupying the same continental region and many of the same watersheds. We conclude that differences are likely caused by contrasting life history attributes between genera, particularly host fish requirements and hermaphroditism. Further, we demonstrate the occurrence of a ‘hotspot’ for genetic diversity in both groups of mussels, occurring in the vicinity of the lower Columbia River drainage. We suggest that stream hierarchy may be responsible for this pattern and may produce similar patterns in other widespread freshwater species.本研究针对原产于北美西部的淡水蚌类——镰珠蚌（Margaritifera falcata），在其绝大部分地理分布范围内开展种群遗传结构调查。本研究利用线粒体序列（mitochondrial sequence）与核微卫星（nuclear microsatellite）数据，发现该物种种群整体遗传分化程度较浅，但种群水平上存在显著遗传结构，且种群遗传多样性极低。我们将上述观测格局与栖息于同一大陆区域、共享多数流域的另一淡水蚌类群（加州无齿蚌/纳氏无齿蚌，Anodonta californiensis/A. nuttalliana）的既往研究结果进行了对比。研究推断，两类群间的遗传格局差异可能源于两属物种不同的生活史特征，尤其是宿主鱼类依赖特性与雌雄同体（hermaphroditism）性状。此外，我们证实两类淡水蚌均存在遗传多样性热点（genetic diversity hotspot），其分布区域位于下哥伦比亚河流域周边。我们推测，河流层级结构可能是该分布格局的成因，且该因素可能在其他广布淡水物种中造就相似的遗传分化模式。