IntroductionQuaternary glaciations, in particular the last glacial maximum (LGM), have shaped the contemporary distribution of many species. In Europe, survival of temperate species during range contractions was mainly associated with refugia in Mediterranean peninsulas, allowing south to north recolonization. Additionally, the Ponto-Caspian refugium provided an east to west migration route.MethodsHere, we investigated genetic diversity and structure of the dispersal-restricted Primula vulgaris Huds., a temperate herb of supposed Caucasian origin, using 12 highly polymorphic nuclear microsatellite loci to trace the colonization of this species in three European regions. We studied 38 populations, namely an eastern mountainous region (Caucasus), a central region (Carpathian Mountains and Dinaric Alps) and a western lowland region (North European Plain). The role of an eastern refugium of the species was tested by performing Approximate Bayesian computation analyses to elucidate its demographic and phylogeographic history, detecting bottleneck and expansion events, and estimating effective (ancestral and current) population sizes and time of divergence.Results and discussionWe found the eastern and central regions featuring the highest allelic richness and genetic differentiation being strong between and within regions. Stepwise-like mutation processes (RST > FST), together with isolation-by-distance patterns, contributed to genetic differentiation. Demographic event models showed that P. vulgaris experienced bottlenecks as well as expansions across its range during the Quaternary glacial cycles, with the last expansion about 6,000, 4,000, and 2,000 generations ago for eastern, central, and western populations, respectively. The best supported origin model pointed to the Caucasus population being closest to an ancestral situation, and from where central and western populations diverged subsequently. Divergence time of the Caucasus populations from an ancestral lineage referred to the Upper Pleistocene (Middle Weichselian). Divergence of Carpathian populations, including a Lower Danube valley corridor, was estimated during and across the LGM (Late Weichselian), confirming central populations as potential secondary cryptic refugium. Western populations recently diverged during the Holocene, most probably in the Atlanticum phase (7,000–3,900 years ago). Within regions, genetic structure was also shaped by latitude, longitude, or altitudinal migration, and for western lowlands, by recent bottleneck and genetic drift processes.

中文翻译：

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越过山丘和遥远的地方：传播受限的报春花（Primula vulgaris）的系统发育地理学和人口迁徙历史

简介第四纪冰川作用，特别是末次盛冰期（LGM），塑造了许多物种的当代分布。在欧洲，温带物种在活动范围缩小期间的生存主要与地中海半岛的避难所有关，从而允许从南到北重新殖民。此外，蓬托里海避难所提供了一条从东到西的迁徙路线。方法在这里，我们研究了限制扩散的遗传多样性和结构报春花Huds.，一种被认为起源于高加索的温带草本植物，利用 12 个高度多态性的核微卫星位点来追踪该物种在三个欧洲地区的殖民情况。我们研究了 38 个人群，即东部山区（高加索）、中部地区（喀尔巴阡山脉和迪纳里克阿尔卑斯山）和西部低地地区（北欧平原）。通过执行近似贝叶斯计算分析来测试该物种东部避难所的作用，以阐明其人口和系统发育历史，检测瓶颈和扩张事件，并估计有效（祖先和当前）种群规模和分歧时间。结果和讨论我们发现东部和中部地区的等位基因丰富度最高，区域间和区域内的遗传分化也很强。类似逐步的突变过程（右英石>F英石）与距离隔离模式一起促进了遗传分化。人口事件模型表明普通假单胞菌在第四纪冰川周期期间，其范围经历了瓶颈和扩张，东部、中部和西部种群的最后一次扩张分别是在约 6,000、4,000 和 2,000 代以前。最受支持的起源模型指出，高加索人口最接近祖先的情况，而中部和西部人口随后开始分化。高加索人群与上更新世（中魏希瑟利安）祖先谱系的分化时间。在末次盛世（Late Weichselian）期间和整个时期对喀尔巴阡山脉种群的分歧（包括多瑙河下游河谷走廊）进行了估计，确认了中心种群是潜在的次要隐秘避难所。西方种群最近在全新世期间出现了分歧，很可能是在大西洋阶段（7,000-3,900年前）。在区域内，遗传结构也受到纬度、经度或海拔迁移的影响，而对于西部低地来说，则受到最近的瓶颈和遗传漂变过程的影响。