Data from: Influence of geography and environment on patterns of genetic differentiation in a widespread submerged macrophyte, Eurasian watermilfoil (Myriophyllum spicatum L., Haloragaceae)

The effects of geographic and environmental variables on the pattern of genetic differentiation have been thoroughly studied, whereas empirical studies on aquatic plants are rare. We examined the spatial genetic differentiation of 58 Myriophyllum spicatum populations distributed throughout China with 12 microsatellite loci, and we analyzed its association with geographic distance, geographic barriers, and environmental dissimilarity using causal modeling and multiple matrix regression with randomization (MMRR) analysis. Two genetic clusters were identified, and their geographic distribution suggested mountain ranges as a barrier to gene flow. The causal modeling revealed that both climate and geographic barriers significantly influenced genetic divergence among M. spicatum populations and that climate had the highest regression coefficient according to the MMRR analysis. This study showed that geography and environment together played roles in shaping the genetic structure of M. spicatum and that the influence of environment was greater. Our findings emphasized the potential importance of the environment in producing population genetic differentiation in aquatic plants at a large geographic scale.

地理与环境变量对遗传分化格局的影响已得到广泛研究，但针对水生植物的相关实证研究仍较为匮乏。本研究以遍布中国境内的58个穗状狐尾藻（Myriophyllum spicatum）种群为研究对象，利用12个微卫星位点（microsatellite loci）分析其空间遗传分化模式，并通过因果建模与随机化多重矩阵回归（multiple matrix regression with randomization, MMRR）分析，探究其与地理距离、地理屏障及环境异质性之间的关联。研究共鉴定出两个遗传聚类群，其地理分布格局显示山脉可作为基因流的阻碍屏障。因果建模结果显示，气候因子与地理屏障均对穗状狐尾藻种群间的遗传分化产生显著影响；且经MMRR分析可知，气候因子的回归系数最高。本研究表明，地理因素与环境因子共同参与塑造了穗状狐尾藻的遗传结构，且环境因子的影响更为显著。本研究结果凸显了在大地理尺度下，环境因子在驱动水生植物种群遗传分化过程中的潜在重要性。