Hampe A, Arroyo J, Jordano P, Petit R J
Depto de Biología Vegetal y Ecología, Universidad de Sevilla, Apdo. 1095, E-41080 Sevilla, Spain.
Mol Ecol. 2003 Dec;12(12):3415-26. doi: 10.1046/j.1365-294x.2003.02006.x.
We studied the phylogeography of alder buckthorn (Frangula alnus), a bird-dispersed shrub or small tree distributed over most of Europe and West Asia and present in three of the four main refugia of West Palaearctic temperate woody plants: the Iberian Peninsula, the Balkans and Anatolia. A total of 78 populations from 21 countries were analysed for chloroplast DNA variation using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and 21 different haplotypes were distinguished. We found a very strong overall population differentiation (GST = 0.81) and phylogeographical structure, and a sharp contrast between the haplotype-rich refugia and the almost completely uniform area of postglacial colonization. The haplotype network comprises three lineages made up of haplotypes from the Iberian Peninsula, Anatolia with the Caucasus, and temperate Europe. The Iberian and the Anatolian branches represent parts of a major lineage that spans over the whole northern Mediterranean Basin and some neighbouring areas and probably dates back to the Tertiary. Many haplotypes of this lineage are distributed locally and most populations are fixed for a single haplotype; these populations have apparently been very stable since their establishment, experiencing negligible gene flow and few mutations. The temperate European lineage consists of one very widespread and abundant plus six locally distributed haplotypes. Four of them are located in Southeast Europe, the putative refugium of all extant temperate European populations. Contrary to populations from Iberia and Anatolia, F. alnus populations from the southeastern European refugium have most genetic variation within populations. Bird-mediated seed dispersal has apparently allowed not only a very rapid postglacial expansion of F. alnus but also subsequent regular seed exchanges between populations of the largely continuous species range in temperate Europe. In contrast, the disjunct F. alnus populations persisting in Mediterranean mountain ranges seem to have experienced little gene flow and have therefore accumulated a high degree of differentiation, even at short distances. Populations from the southern parts of the glacial refugia have contributed little to the postglacial recolonization of Europe, but their long-term historical continuity has allowed them to maintain a unique store of genetic variation.
我们研究了鼠李科鼠李属的桤叶鼠李（Frangula alnus）的系统地理学，它是一种由鸟类传播种子的灌木或小乔木，分布于欧洲大部分地区和西亚，并且存在于古北区西部温带木本植物四个主要避难所中的三个：伊比利亚半岛、巴尔干半岛和安纳托利亚。我们利用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）分析了来自21个国家的总共78个种群的叶绿体DNA变异，区分出了21种不同的单倍型。我们发现了非常强烈的总体种群分化（GST = 0.81）和系统地理结构，并且在单倍型丰富的避难所与几乎完全一致的冰期后殖民区域之间形成了鲜明对比。单倍型网络由三个谱系组成，分别由来自伊比利亚半岛、安纳托利亚及高加索地区和温带欧洲的单倍型构成。伊比利亚和安纳托利亚分支代表了一个跨越整个地中海北岸盆地及一些邻近地区的主要谱系的一部分，其历史可能追溯到第三纪。这个谱系的许多单倍型是局部分布的，并且大多数种群固定为单一单倍型；这些种群自形成以来显然非常稳定，基因流动可忽略不计，发生的突变也很少。温带欧洲谱系由一个分布非常广泛且数量众多的单倍型以及六个局部分布的单倍型组成。其中四个位于欧洲东南部，这里被认为是所有现存温带欧洲种群的避难所。与来自伊比利亚半岛和安纳托利亚的种群相反，来自欧洲东南部避难所的桤叶鼠李种群在种群内部具有最多的遗传变异。鸟类介导的种子传播显然不仅使得桤叶鼠李在冰期后得以非常迅速地扩张分布范围，而且使得在温带欧洲这个大体连续的物种分布区内，不同种群之间随后能够定期进行种子交换。相比之下，在地中海山脉中持续存在的间断分布的桤叶鼠李种群似乎经历了很少的基因流动，因此即使在短距离内也积累了高度的分化。来自冰川避难所南部的种群对欧洲冰期后的重新定居贡献很小，但其长期的历史连续性使其能够保留独特的遗传变异库。
