Phylogeographic connections between geographic distribution and genetic structure in the tree species constituting the Japanese beech forest distributed along the Japan Sea side

对分布在日本海沿岸的日本山毛榉林树种的地理分布与遗传结构之间的系统地理联系进行了研究。首先，对日本海侧日本山毛榉林中3种灌木（白冬青、北方山毛榉、大豆瓣水蚤）5个居群各2个个体的线粒体DNA限制性片段长度多态性（RFLP）进行了初步调查。北方粳稻品种和大豆科植物品种的多态性较少，而白菖蒲品种的多态性较高。其次，利用12个种群的357个个体，进一步研究了leucoclada的mtDNA RFLP。基因多样性分析表明，西南居群遗传变异较大，东北居群遗传变异较大。这种地理变异模式可能是由于末次冰期极大期的地理分布和随后的物种定植所致。现在,一项初步调查发现叶绿体DNA多态地区(cpDNA)和基于cpDNA phylogeographic分析多态性I.Leucoclada正在进行。并将其mtDNA和cpDNA的系统地理结构与油麻进行比较。这一比较将有助于揭示沿日本海分布的日本山毛榉林树种的地理分布与遗传结构之间的系统地理联系。

Phylogeographic connections between geographic distribution and genetic structure were studied in the tree species constituting the Japanese beech forest distributed along the Japan Sea side. First, preliminary surveys on restriction fragment length polymorphism (RFLP) in mitochondrial DNA (mtDNA) were conducted using two individuals from each of five populations of the three shrub species (Ilex leucoclada, Aucuba japonica var.borealis, Daphniphyllum macropodum var.humile), which are component species in Japanese beech forest on the Japan Sea side. Few polymorphism were detected in A.japonica var.borealis and D.macropodum var.humile), whereas I.Leucoclada showed a high level of polymorphism. Second, the RFLP in mtDNA for I.Leucoclada was further studied using 357 individuals from 12 populations. Gene diversity analysis showed that the genetic variation within populations was higher in the southwestern populations man in northeastern populations. This geographic pattern of variation may be due to the geographic distribution in the last glacial maximum and subsequent colonization for the species. Now, a preliminary survey to detect polymorphic regions in chloroplast DNA (cpDNA) and the phylogeographic analysis based on the cpDNA polymorphism are being conducted for I.Leucoclada. The phylogeographic structures of mtDNA and cpDNA in I.Leucoclada will be compared with those in Fagus crenata. This comparison will contribute to reveal the phylogeographic connections between geographic distribution and genetic structure in the tree species constituting the Japanese beech forest distributed along the Japan Sea side.