Population genetics of Nymphoides peltata (S.G.Gmel.) Kuntze

Clonal diversity of Nymphoides peltata was estimated by genome-wide SNPs in Japan. A total of 27 clones were detected by considering the genetic distances between clones over a distance threshold. The number of the clones were greatly smaller than the estimate by a previous study based on SSR (Short Sequence Repeats) markers. This may be because populations of the species had diminished due to environmental deterioration over the past decade. Alternatively, the fewer samples analyzed in this study or technical problems of SSR markers used in the previous study may be another reasons. The populations of N. peltata were genetically differentiated between the west and east regions of the Japanese Archipelago. Artificial movements of the species were strongly suggested in a few populations.

本研究采用全基因组单核苷酸多态性（genome-wide SNPs）标记，对日本境内的莕菜（Nymphoides peltata）的克隆多样性展开评估。通过设定遗传距离阈值，基于克隆间的遗传距离进行判定，共检测到27个克隆。该研究检出的克隆数量远少于此前基于简单序列重复（Short Sequence Repeats，SSR）标记的研究所得到的估计值。这一差异可能源于近十年来环境恶化导致该物种种群规模缩减；也有可能是本研究样本量偏少，或是此前研究中使用的SSR标记存在技术局限。日本列岛东西两侧的莕菜种群存在显著遗传分化。多项证据强烈提示，少数种群中存在该物种的人为引种事件。