Abstract Genetic variation is a major component of plant development and adaptation, and recent studies have shown that genetic variation among plant species can have important ecological effects. Oriental beech (Fagus orientalis Lipsky) is a dominant tree species in the Hyrcanian forests, where it occupies approximately 18 % of the forested area. In this study, nine expressed sequence tag simple sequence repeat (EST-SSR) markers were used to determine the genetic diversity and structure of Iranian Oriental beech populations growing at different altitudes. We further compared the genetic structures of the Iranian populations to a F. orientalis and a Fagus sylvatica L. population from the hybrid zone of the two taxa in southeast Europe, and to a F. sylvatica population from central Europe. All populations showed a high genetic diversity, which was similar to other F. orientalis and F. sylvatica populations from Europe. The genetic differentiation among Iranian beech populations was very low. In contrast, distinct genetic differentiation was found between the Iranian populations and the analyzed European populations (F. orientalis and F. sylvatica). One EST-SSR was identified to differentiate (GST: 0.503) between F. orientalis and F. sylvatica with very pronounced allele frequency differences between taxa. Specifically, the Fagus sylvatica characteristic allele 189 was almost absent from all Iranian populations and present in low frequencies in F. orientalis populations from other regions. This study helps to extend the knowledge of genetic diversity and genetic structure of Iranian Oriental beech populations. It further gives insights into the genetic differentiation between F. orientalis populations from the center and the edge of the species’ distribution range as well as between Oriental and European beech.

中文翻译：

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伊朗和欧洲东方和欧洲山毛榉种群的遗传多样性和结构

摘要 遗传变异是植物发育和适应的重要组成部分，最近的研究表明，植物物种间的遗传变异具有重要的生态效应。东方山毛榉 (Fagus orientalis Lipsky) 是希尔卡尼亚森林中的优势树种，约占森林面积的 18%。在这项研究中，九个表达序列标签简单序列重复 (EST-SSR) 标记被用于确定生长在不同海拔的伊朗东方山毛榉种群的遗传多样性和结构。我们进一步将伊朗种群的遗传结构与来自东南欧两个分类群的杂交区的 F. orientalis 和 Fagus sylvatica L. 种群以及来自中欧的 F. sylvatica 种群进行了比较。所有种群都表现出很高的遗传多样性，这与来自欧洲的其他 F. orientalis 和 F. sylvatica 种群相似。伊朗山毛榉种群之间的遗传分化非常低。相比之下，在伊朗种群和分析的欧洲种群（F. orientalis 和 F. sylvatica）之间发现了明显的遗传差异。一种 EST-SSR 被鉴定为区分（GST：0.503）东方香菇和香樟木，分类群之间具有非常显着的等位基因频率差异。具体来说，Fagus sylvatica 特征等位基因 189 在所有伊朗种群中几乎不存在，而在其他地区的 F. orientalis 种群中以低频率存在。这项研究有助于扩展对伊朗东方山毛榉种群遗传多样性和遗传结构的认识。它进一步深入了解 F.