Data from: Genetic structure and invasion history of the house mouse (Mus musculus domesticus) in Senegal, West Africa: a legacy of colonial and contemporary times

Knowledge of the genetic make-up and demographic history of invasive populations is critical to understand invasion mechanisms. Commensal rodents are ideal models to study whether complex invasion histories are typical of introductions involving human activities. The house mouse Mus musculus domesticus is a major invasive synanthropic rodent originating from South-West Asia. It has been largely studied in Europe and on several remote islands, but the genetic structure and invasion history of this taxon have been little investigated in several continental areas, including West Africa. In this study, we focussed on invasive populations of M. m. domesticus in Senegal. In this focal area for European settlers, the distribution area and invasion spread of the house mouse is documented by decades of data on commensal rodent communities. Genetic variation at one mitochondrial locus and 16 nuclear microsatellite markers was analysed from individuals sampled in 36 sites distributed across the country. A combination of phylogeographic and population genetics methods showed that there was a single introduction event on the northern coast of Senegal, from an exogenous (probably West European) source, followed by a secondary introduction from northern Senegal into a coastal site further south. The geographic locations of these introduction sites were consistent with the colonial history of Senegal. Overall, the marked microsatellite genetic structure observed in Senegal, even between sites located close together, revealed a complex interplay of different demographic processes occurring during house mouse spatial expansion, including sequential founder effects and stratified dispersal due to human transport along major roads.

解析入侵种群的遗传组成与种群历史，对于阐明生物入侵机制至关重要。人伴生啮齿类是探究人类活动介导的物种引入是否普遍伴随复杂入侵历史的理想模型类群。小家鼠（Mus musculus domesticus）是起源于西南亚的主要人伴生入侵啮齿类物种。该亚种已在欧洲及诸多偏远岛屿被广泛研究，但包括西非在内的多数大陆区域中，该类群的遗传结构与入侵历史却鲜有系统探究。本研究聚焦于塞内加尔境内的小家鼠（M. m. domesticus）入侵种群。作为欧洲殖民者的核心定居区域，塞内加尔的小家鼠分布范围与入侵扩散历程，可通过数十年间的人伴生啮齿类群落调查数据得到有效佐证。研究人员对覆盖塞内加尔全境36个采样点的个体，检测并分析了1个线粒体基因座与16个核微卫星标记的遗传变异。结合谱系地理学与种群遗传学方法的联合分析结果显示：小家鼠首先通过单次引入事件抵达塞内加尔北部海岸，其来源为域外种群（大概率为西欧种群）；随后发生二次引入事件，即从塞内加尔北部扩散至更南部的一处沿海区域。上述两次引入事件的地理分布位置，与塞内加尔的殖民历史高度契合。整体而言，即便在地理位置相近的采样点间，塞内加尔境内小家鼠也呈现出显著的微卫星遗传结构，这揭示了其空间扩张过程中多种种群动态过程的复杂相互作用，包括逐步奠基者效应以及沿主要公路的人类运输介导的分层扩散模式。