Various plant species are endemic to the Korean Peninsula, but their evolutionary divergence and establishment are poorly understood. One of these, Lespedeza maritima, has been proposed as either a hybrid (L. cyrtobotrya × L. maximowiczii) or a synonym of L. thunbergii. A distinct taxon, L. uekii, has been proposed for inland populations. We investigated genetic diversity and structure in L. maritima and related taxa to resolve this. Genotypes of L. maritima (n = 244, including L. uekii) were determined using 12 microsatellite loci, then compared with those of related species. Genetic diversity within L. maritima was estimated, and Bayesian clustering analysis was used to represent its genetic structure and that of related taxa. Its distribution during the last glacial maximum (LGM) was predicted using ecological niche modelling (ENM). Neighbour-joining (NJ) analysis and principal coordinate analysis (PCoA) were used to investigate relationships among species. Bayesian tree based on nuclear ribosomal internal transcribed spacers (nrITS) was also reconstructed to show relationships and divergence time among species. Morphological features were examined using flower characteristics. In result, expected heterozygosity (HE) and allelic richness (AR) within L. maritima were higher in southern than northern populations. Bayesian clustering analysis largely assigned populations to two clusters (K = 2) (south vs. north). The ENM showed that L. maritima occurred around the East China Sea and Korean Strait land bridge during the LGM. Compared with other Lespedeza species, L. maritima was assigned to an independent cluster (K = 2–5), supported by the NJ, PCoA, Bayesian tree and morphological examination results. Lespedeza maritima and L. uekii were clustered to one clade on Bayesian tree. Given results, current L. maritima populations derive from post-LGM colonization away from southern refugia. The type L. uekii, which grows inland, is thought synonym of L. maritima. In addition, L. maritima is considered a distinct species, compared with related taxa.

中文翻译：

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基于微卫星位点的韩国特有灌木胡桃（豆科）的历史迁移和分类实体

各种植物物种是朝鲜半岛特有的，但它们的进化分歧和建立却知之甚少。其中之一，Lespedeza maritima，已被提议作为杂种（L. cyrtobotrya × L. maximowiczii）或 L. thunbergii 的同义词。一个独特的分类群 L. uekii 已被提议用于内陆种群。我们研究了 L. maritima 和相关分类群的遗传多样性和结构以解决这个问题。使用 12 个微卫星位点确定 L. maritima（n = 244，包括 L. uekii）的基因型，然后与相关物种的基因型进行比较。估计了 L. maritima 内的遗传多样性，并使用贝叶斯聚类分析来表示其遗传结构和相关分类群的遗传结构。使用生态位模型（ENM）预测其在末次盛冰期（LGM）的分布。邻接 (NJ) 分析和主坐标分析 (PCoA) 用于研究物种之间的关系。还重建了基于核核糖体内部转录间隔 (nrITS) 的贝叶斯树，以显示物种之间的关系和分歧时间。使用花特征检查形态特征。结果，南部种群的预期杂合性（HE）和等位基因丰富度（AR）在南部种群中高于北部种群。贝叶斯聚类分析主要将人口分配给两个聚类（K = 2）（南与北）。ENM 显示 L. maritima 在 LGM 期间出现在东海和朝鲜海峡陆桥附近。与其他胡枝子属物种相比，L. maritima 被分配到一个独立的集群（K = 2-5），由 NJ、PCoA、贝叶斯树和形态学检查结果。Lespedeza maritima 和 L. uekii 在贝叶斯树上聚集成一个进化枝。鉴于结果，目前的 L. maritima 种群来自远离南部避难所的 LGM 后殖民化。生长在内陆的 L. uekii 被认为是 L. maritima 的同义词。此外，与相关分类群相比，L. maritima 被认为是一个独特的物种。