Tree species of minor commercial importance are mostly neglected both in large-scale genetic surveys and gene conservation programs. Gene conservation measures of forest trees focus on the preservation of intra-species genetic variability, which is a prerequisite of species’ adaptive evolutionary potential enabling it to survive unfavourable conditions. Therefore, variation levels within populations as well as inter-population differentiation patterns need to be assessed under various geographical and evolutionary setups. We studied genetic variation of a widespread, but subdominant tree species, Acer campestre L., in 25 populations located close to the rear edge of the Holocene colonisation in Bosnia and Herzegovina at ten nuclear microsatellite loci. Genetic differentiation within this region was very weak, indicating a lack of strong barriers to gene flow despite range fragmentation. In spite of this, significant isolation by distance was revealed, along with isolation by environment related to temperature. We suggest phenological isolation as the explanation of isolation by environment. Moreover, the group of sub-Mediterranean populations appeared to diverge from the interior populations: they exhibit higher gene diversity, form a separate cluster in the neighbour-joining tree based on chord genetic distances, and show different proportions of gene pools identified by the Bayesian analysis of population structure. As the territory under study is located close to several important glacial refugia for tree species, an origin from different refugial populations may explain the pattern of weak but recognisable genetic differentiation between interior and sub-Mediterranean populations. A genetic bottleneck in several sub-Mediterranean populations was attributed to more recent colonisation events. The results suggest that genetic differentiation associated with the origin from different glacial refugia was not erased by gene flow even in rear-edge populations, and needs to be taken into consideration in gene conservation programs.

具有较小商业意义的树种在大规模遗传调查和基因保护计划中都被忽略。林木的基因保存措施集中于物种内部遗传变异的保存，这是物种适应性进化潜力使其能够在不利条件下生存的前提。因此，需要在各种地理和进化背景下评估种群内的变异水平以及种群间的分化模式。我们研究了一种广泛但占优势的树种宏cer樟树的遗传变异L.，位于波斯尼亚和黑塞哥维那全新世殖民地后缘附近的25个人口中的10个微卫星位点。该区域内的遗传分化非常弱，表明尽管存在距离片段化，但缺乏强大的基因流动障碍。尽管如此，仍显示出明显的距离隔离，以及与温度相关的环境隔离。我们建议使用物候隔离作为环境隔离的解释。此外，地中海次亚种群似乎与内部种群不同：它们表现出更高的基因多样性，根据和弦遗传距离在相邻的邻树中形成一个单独的簇，并显示出由贝叶斯确定的不同比例的基因库人口结构分析。由于研究区域靠近几个重要的树种冰川避难所，因此，来自不同避难所种群的起源可能解释了内陆种群与地中海下种群之间弱但可识别的遗传分化模式。一些近地中海人口的遗传瓶颈归因于最近的殖民化事件。结果表明，即使在后缘人群中，与来自不同冰川避难所起源相关的遗传分化也没有被基因流动所消除，因此在基因保护计划中需要予以考虑。一些近地中海人口的遗传瓶颈归因于最近的殖民化事件。结果表明，即使在边缘人群中，与来自不同冰川避难所起源相关的遗传分化也没有被基因流动所消除，因此在基因保护计划中需要予以考虑。一些近地中海人口的遗传瓶颈归因于最近的殖民化事件。结果表明，即使在后缘人群中，与来自不同冰川避难所起源相关的遗传分化也没有被基因流动所消除，因此在基因保护计划中需要予以考虑。