The phylogeographic structure of Japanese coniferous species as revealed by genetic markers
The phylogeographic structure of Japanese coniferous species as revealed by genetic markers
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作者：
Y. Tsumura
本文综述了利用多态等位酶和细胞器（叶绿体和线粒体）DNA标记研究日本针叶树的系统地理学。3种冷杉的mtDNA多态性显示出明显的地理分异。同工酶标记表明，该菌株具有明确的遗传序列，无mtDNA多态性。在最后一次冰期期间，这些物种的避难所可能位于日本西南太平洋一侧。根据同工酶分析，黑松可能是从西伯利亚向南从北海道迁移到日本中部较高的山区。细花松的线粒体DNA多态性明显区分了细花松的五谷属和细花松，表明后者的避难所位于末次冰期中部山区南部。目前居住在中部高地、东北和北海道的人口大概是通过这些难民的殖民建立起来的。利用等位酶和DNA标记对日本柳杉的系统地理分析没有发现明显的规律。然而，微卫星分析显示，在末次冰期假定的避难所中，等位基因多样性最高。同工酶分析表明，长尾Chamaecyparis obtusa具有明确的同源性。近年来，大量基于表达序列标签的基因座被开发出来用于群体和基因组定位。日本柳杉（Cryptomeria japonica）和长叶蝉（Chamaecyparis obtusa）分属不同科，但基于叶绿体序列数据的分子系统发育表明，它们亲缘关系密切，且长叶蝉的序列标记位点标记在长叶蝉中具有很高的适用性。利用这些标记，研究人员试图弄清这两个物种的遗传结构。本文还讨论了迄今为止最成功的阐明上述物种遗传结构的方法以及与日本针叶树有关的其他系统地理学问题。
The phylogeography of Japanese conifers studied using polymorphic allozyme and organelle (chloroplast and mitochondrial) DNA markers is reviewed. Three Abies species showed a clear geographical dine based on mtDNA polymorphisms. Allozyme markers revealed a clear genetic dine in A. mariesii, with no mtDNA polymorphism. Refugia of these species during the last glaciation were probably located along the southwestern Pacific side of Japan. Based on allozyme analysis, Pinus pumila may have migrated from Siberia southward from Hokkaido to higher mountains in central Japan. Mitochondrial DNA polymorphisms clearly differentiated the pentaphylla and parviflora varieties of Pinus parviflora and suggest that refugia of the latter species were located south of the central mountains of Chubu district during the last glaciation. Current populations in the Chubu highlands, Tohoku, and Hokkaido presumably became established by colonization from these refugia. Phylogeographic analysis of Cryptomeria japonica using allozymes and DNA markers did not reveal distinct patterns. However, microsatellite analysis revealed highest allelic diversity in putative refugia of the last glaciation. Allozyme analysis of Chamaecyparis obtusa revealed a clear dine. Recently, substantial numbers of loci based on expressed sequence tags for population and genome mapping were developed. Cryptomeria japonica and Chamaecyparis obtusa belong to different families, but molecular phylogeny based on chloroplast sequence data revealed that they are closely related and that sequence tag site markers of C. japonica are highly applicable to C. obtusa. Using such markers, researchers have attempted to clarify the genetic structure of the two species. This paper also discusses the most successful approaches (to date) for elucidating the genetic structure of the above-mentioned species and other phylogeographic issues related to Japanese conifers.