Data from: Within-range translocations and their consequences in European larch

In contrast to biological invasions, translocations of individuals within a species range are understudied, due to difficulties in systematically detecting them. This results in limited knowledge about the corresponding processes and uncertainties regarding the status of extant populations. European larch, a forest tree whose fragmented native distribution is restricted to the Alps and to other Central European mountains, has been massively planted for at least 300 years. Here we focus on the genetic characterization of translocations having taken place within its native range. Microsatellite variation at 13 nuclear loci and sequence data of two mitochondrial DNA fragments were analyzed on the basis of a comprehensive range-wide population sample. Two complementary methods (Geneclass and Structure) were used to infer translocation events based on nuclear data whereas mitochondrial data were used for validation of these inferences. Using Geneclass, we found translocation events in a majority of populations. Additional cases of translocation and many instances of admixture were identified using Structure, thanks to the clear-cut ancestral genetic structure detected in this species. In particular, a strong divide between Alpine and Central European populations, also apparent at mitochondrial markers, helped uncover details on translocation events and related processes. Translocations and associated admixture events were found to be heterogeneously distributed across the species range, with a particularly high frequency in Central Europe. Furthermore, translocations frequently involved multiple geographic sources, some of which were over-represented. Our study illustrates the importance of range-wide investigations for tracing translocations back to their origins and for revealing some of their consequences. It provides some first clues for developing suitable conservation and management strategies.与生物入侵形成鲜明对比的是，物种分布范围内的个体易位研究仍严重不足，这是因为系统性检测此类易位存在诸多技术难题。这导致学界对相关过程的认知极为有限，且对现存种群的现状存在诸多不确定性。 欧洲落叶松（European larch）是一种森林树种，其碎片化的原生分布仅局限于阿尔卑斯山脉及其他中欧山地，且已有至少300年的大规模人工种植历史。 本研究聚焦于其原生分布范围内发生的个体易位的遗传特征解析。研究基于全覆盖的种群采样方案，对13个核基因座的微卫星变异以及两段线粒体DNA片段的序列数据开展了分析。本研究采用两种互补的分析工具（Geneclass与Structure），基于核基因组数据推断易位事件，并借助线粒体基因组数据对上述推断结果进行验证。 通过Geneclass分析，我们在多数采样种群中均检测到易位事件的存在。借助该物种清晰可辨的祖先遗传结构，Structure分析进一步识别出更多易位案例以及大量遗传混杂实例。 尤为关键的是，阿尔卑斯种群与中欧种群之间存在显著的遗传分化，这一特征在线粒体标记中同样有所体现，该分化特征为我们深入揭示易位事件及其相关过程的细节提供了重要依据。 研究发现，易位事件及伴随的遗传混杂事件在该物种的分布范围内呈现异质性分布，其中中欧地区的发生频率尤其高。此外，多数易位事件涉及多个地理来源的种群，部分来源种群的贡献占比甚至超出正常水平。 本研究彰显了全覆盖范围采样对于追踪易位事件的起源、揭示其相关影响的重要意义。同时，本研究也为制定合理的物种保护与管理策略提供了首批关键参考依据。