Tracing the origin of Oriental beech stands across Western Europe and reporting hybridization with European beech – implications for assisted gene flow

The benefits and risks of human-aided translocation of individuals within the species range, assisted gene flow (AGF), depend on the genetic divergence, on the rate and direction of hybridization, and on the climate transfer distance between the host and donor populations. In this study, we explored the use of Oriental beech (Fagus sylvatica subsp. orientalis), growing from Iran to the Balkans, for AGF into European beech populations (F. sylvatica subsp. Sylvatica) that increasingly suffer from climate warming. Using samples from natural populations of Oriental and European beech and microsatellite loci, we identified 5 distinct genetic clusters in Oriental beech with a divergence (FST) of 0.15 to 0.25 from European beech. Using this knowledge, we traced the origin of 11 Oriental beech stands in Western Europe established during the 20th century. In two stands of Greater Caucasus origin, we found evidence for extensive hybridization, with 18% and 41% of the seedlings having hybrid statu..., See the Methods section of Kurz et al. 2023.,在物种种群分布范围内开展的人工辅助个体迁移，即辅助基因流（assisted gene flow, AGF），其效益与风险取决于遗传分化程度、杂交发生速率与方向，以及受体种群与供体种群间的气候迁移距离。本研究以分布范围从伊朗延伸至巴尔干半岛的东方山毛榉（Fagus sylvatica subsp. orientalis）为研究材料，探索将其用于辅助基因流，以应对日益受气候变暖威胁的欧洲山毛榉种群（F. sylvatica subsp. Sylvatica）。研究团队采用东方山毛榉与欧洲山毛榉的天然种群样本及微卫星位点进行分析，鉴定出东方山毛榉可划分为5个独立的遗传簇，其与欧洲山毛榉的遗传分化系数（FST）介于0.15至0.25之间。基于上述研究结果，我们追溯了20世纪于西欧定植的11处东方山毛榉林分的起源。在两处源自大高加索地区的林分中，研究团队发现了大规模杂交的证据，分别有18%与41%的幼苗为杂交个体……详见Kurz等2023年的研究方法部分。