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榉属(Zelkova)是包含6个种的榆科小属,呈东亚、西亚和南欧间断分布。该文基于DNA序列trnL-trnF和ITS构建了榉属的分子系统发育树,大体上把此属分为3个分支,分别对应东亚、西亚和南欧的种类,与前人仅依据ITS序列的结果不同。生物地理的扩散和隔离分化分析(DIVA)表明,榉属的原始祖先分布区可能是欧亚北温带,包括了东亚、西亚和南欧的某个大的区域。分化过程以隔离分化为主要特征,即3个分布区域是逐步隔离分化的。由于东亚的物种多样性,北太平洋有可能是起源中心。榉属的现代分布格局可能主要是由于渐新世发生的古地中海西退、中新世发生的青藏高原大范围隆升,以及第四纪冰川活动引起的分布区的收缩。
Zelkova is a small genus of Ulmus that contains six species, distributed intermittently in East Asia, West Asia and Southern Europe. In this paper, we constructed a molecular phylogenetic tree based on the DNA sequence trnL-trnF and ITS, which is divided into three branches, corresponding to the species of East Asia, West Asia and South Europe. Compared with the previous results based on ITS sequences different. Biogeographical Diffusion Differentiation Analysis (DIVA) shows that the original ancestral distribution area of the genus beech may be the Eurasian north temperate zone, including a large area of East Asia, West Asia and southern Europe. Differentiation process to isolate and differentiate as the main feature, that is, three distribution areas are gradually isolated and differentiated. Due to the species diversity in East Asia, the North Pacific may be the center of origin. The modern distribution pattern of the genus Zelkova may be mainly caused by the western depression of the Oligocene in the Oligocene, the large uplift of the Qinghai-Tibet Plateau in the Miocene, and the contraction of the distribution caused by the Quaternary glaciation.