Genetic Structure of Hybrid Zones between Pinus pumila and P. pariflora var. pentaphylla.

矮松是一种匍匐灌木，主要生长于高寒地区。五叶松是一种生长在亚高山到山区的高大乔木。两种间的杂交区主要见于日本东北地区的山区。松种具有父本cpDNA遗传和母本mtDNA遗传。以往的研究表明，父本cpDNA从细小假单胞虫流向细小假单胞虫，而母本mtDNA则从细小假单胞虫流向细小假单胞虫。除了诊断性的cpDNA和mtDNA标记外，本研究还开发了多种核DNA标记。我们对红松的ESTP引物进行了筛选，最终获得了10个适用于矮矮松和细小矮松的诊断标记位点。利用分子杂交指数分析了东津山和谷川山杂交带的遗传结构。杂交指数显示了所检测等位基因中矮秆草标记等位基因的百分比。在东azazuma中，冷杉和津杉组成的亚高山针叶林（1800 ~ 1900 m）以下的植物遗传上与parviflora相似，杂交指数平均值为0.073。而冷杉林以上植物的杂交指数为0.949。这一结果表明，两种物种之间的基因流动被阿贝-津加森林有效地阻断了。在缺乏亚高山针叶林的谷川地区，杂交指数随各个体海拔高度的变化在0 ~ 1之间连续变化。我们还开发了适用于矮叶假蝇和细小植物假蝇的微卫星标记。我们用磁珠浓缩带有微卫星的DNA片段。我们测定了大约300个克隆的核苷酸序列，发现86个独特的克隆具有微卫星。

Pinus pumila is a creeping shrub which dominates in alpine zone. Pinus parviflora var. pentaphylla is a tall tree in sub-alpine to montane zones. Hybrid zones between the two species are observed mainly in mountains of Tohoku district, Japan. Pinus species exhibit a paternal cpDNA inheritance and a maternal mtDNA inheritance. Previous studies showed that paternal cpDNA flowed from P. parviflora to P. pumila, and in contrast maternal mtDNA from P. pumila to P. parviflora. In addition to diagnostic cpDNA and mtDNA markers, we developed multiple nuclear DNA markers in the present study. We carried out the screening of ESTP primers of Pinus taeda, and finally obtained ten diagnostic marker loci applicable to P. pumila and P. parviflora. Genetic structure of hybrid zones of Mt. Higasiazuma and Mts. Tanigawa were examined by molecular hybrid index. The hybrid index show the percentage of P. pumila marker alleles in the alleles examined. In Higasiazuma, the plants below the sub-alpine conifer forest composed of Abies and Tsuga (1800-1900 m) were genetically similar to P. parviflora, and the average of their hybrid index was 0.073. While, the hybrid index of the plants above the Abies-Tsuga forest were 0.949. This results suggest that the gene flow between the two species are effectively obstructed by the Abies-Tsuga forest. In Tanigawa lacking the sub-alpine conifer forest, hybrid index varied continuously from 0 to 1 according to the altitude of each individuals.We also developed microsatellite markers applicable to P. pumila and P. parviflora. We concentrated DNA fragments having microsatellites by magnetic beads. We determined the nucleotide sequences of about 300 clones, and found 86 unique clones having microsatellites.