Data from: Bayesian inference of a complex invasion history revealed by nuclear and chloroplast genetic diversity in the colonizing plant, Silene latifolia

Species invading new ranges are subject to a series of demographic events that can strongly shape genetic diversity. Describing this demographic history is important for understanding where invasive species come from and how they spread, and is critical to testing hypotheses of post-invasion adaptation. Here, we analyze nuclear and chloroplast genetic diversity to study the invasion history of the widespread colonizing weed, Silene latifolia (Caryophyllaceae). Bayesian clustering and PCA revealed strong population structure in the native range of Europe and although genotypes from multiple native sources were present in the introduced range of North America, the spatial distribution of genetic variance was dramatically reorganized. Using approximate Bayesian computation (ABC), we compared support for different invasion scenarios, including the number and size of independent introduction events and the amount of admixture occurring between sources of introduced genotypes. Our results supported independent introductions into eastern and western North America, with the latter forming a bridgehead for a secondary invasion into the Great Lakes region of central North America. Despite small estimated founder population sizes, the duration of the demographic bottleneck after the initial introduction appeared extremely short-lived. This pattern of repeated colonization and rapid expansion has effectively eroded the strong population structure and cyto-nuclear associations present in Europe, but has retained overall high genetic diversity since invasion. Our results highlight the flexibility of the ABC approach for constructing a narrative of the demographic history of species invasions, and provide baseline for future studies of evolutionary changes in introduced S. latifolia populations.

入侵至新分布区的物种会经历一系列种群动态事件，这些事件可显著塑造其遗传多样性。解析此类种群历史动态，不仅有助于明确入侵物种的起源与扩散路径，更是检验入侵后适应假说的关键环节。本研究针对广布性入侵杂草白麦瓶草（*Silene latifolia*，石竹科），通过分析核基因组与叶绿体基因组的遗传多样性，解析其入侵历史。贝叶斯聚类与主成分分析（Principal Component Analysis）结果显示，该物种在欧洲原生分布区存在显著的种群结构；尽管北美引入分布区存在来自多个原生源地的基因型，但遗传变异的空间分布已发生显著重塑。本研究采用近似贝叶斯计算（Approximate Bayesian Computation）方法，对比了不同入侵情景的支持度，包括独立引入事件的数量与规模、引入基因型源地间的遗传混合程度。研究结果支持北美东部与西部存在独立引入事件，其中西部种群作为二次入侵的桥头堡，介导了后续对北美中部五大湖区域的入侵。尽管估算得到的奠基者种群规模较小，但初始引入后的种群瓶颈持续时长极短。这种反复定植与快速扩张的模式，有效消解了欧洲原生种群中显著的种群结构与质核关联特征，但入侵后整体遗传多样性仍维持在较高水平。本研究凸显了近似贝叶斯计算方法在构建物种入侵种群历史叙事中的灵活性，并为后续针对引入白麦瓶草种群的演化变化研究提供了研究基线。