Rokas Antonis, Atkinson Rachel J, Webster Lucy, Csóka György, Stone Graham N
Institute of Cell, Animal and Population Biology, University of Edinburgh, West Mains Road, King's Buildings, Edinburgh EH9 3JT, UK.
Mol Ecol. 2003 Aug;12(8):2153-74. doi: 10.1046/j.1365-294x.2003.01894.x.
Many studies have addressed the latitudinal gradients in intraspecific genetic diversity of European taxa generated during postglacial range expansion from southern refugia. Although Asia Minor is known to be a centre of diversity for many taxa, relatively few studies have considered its potential role as a Pleistocene refugium or a potential source for more ancient westward range expansion into Europe. Here we address these issues for an oak gallwasp, Andricus quercustozae (Hymenoptera: Cynipidae), whose distribution extends from Morocco along the northern coast of the Mediterranean through Turkey to Iran. We use sequence data for a fragment of the mitochondrial gene cytochrome b and allele frequency data for 12 polymorphic allozyme loci to answer the following questions: (1). which regions represent current centres of genetic diversity for A. quercustozae? Do eastern populations represent one refuge or several discrete glacial refugia? (2). Can we infer the timescale and sequence of the colonization processes linking current centres of diversity? Our results suggest that A. quercustozae was present in five distinct refugia (Iberia, Italy, the Balkans, southwestern Turkey and northeastern Turkey) with recent genetic exchange between Italy and Hungary. Genetic diversity is greatest in the Turkish refugia, suggesting that European populations are either (a). derived from Asia Minor, or (b). subject to more frequent population bottlenecks. Although Iberian populations show the lowest diversity for putatively selectively neutral markers, they have colonized a new oak host and represent a genetically and biologically discrete entity within the species.
许多研究探讨了欧洲类群在末次冰期后从南部避难所进行范围扩张期间种内遗传多样性的纬度梯度。尽管小亚细亚是许多类群的多样性中心，但相对较少的研究考虑过其作为更新世避难所的潜在作用，或作为更古老的向西扩张进入欧洲的潜在源头的作用。在此，我们针对一种栎瘿蜂Andricus quercustozae（膜翅目：瘿蜂科）探讨这些问题，其分布范围从摩洛哥沿着地中海北岸延伸至土耳其，再到伊朗。我们使用线粒体基因细胞色素b片段的序列数据以及12个多态性等位酶位点的等位基因频率数据来回答以下问题：（1）哪些区域代表了A. quercustozae当前的遗传多样性中心？东部种群代表一个避难所还是几个离散的冰期避难所？（2）我们能否推断连接当前多样性中心的定殖过程的时间尺度和顺序？我们的结果表明，A. quercustozae存在于五个不同的避难所（伊比利亚、意大利、巴尔干半岛、土耳其西南部和土耳其东北部），且意大利和匈牙利之间近期存在基因交流。土耳其避难所的遗传多样性最高，这表明欧洲种群要么（a）源自小亚细亚，要么（b）经历了更频繁的种群瓶颈。尽管伊比利亚种群在假定的选择性中性标记方面表现出最低的多样性，但它们已定殖到一种新的栎树宿主上，并且在该物种内代表一个遗传和生物学上离散的实体。
