影响披碱草属植物遗传分化和亲缘关系的地理因素分析

用微卫星标记法对产自中国青藏高原和蒙古高原地区9种披碱草属（Elymus L．）植物的40个居群进行遗传变异和亲缘关系分析，居群问遗传相似系数为0．020～0．957，居群间遗传距离与地理因素关系密切。以垂穗披碱草（Elymus nutctns Griseb．）为例，采用二维和三维Mantel检验，对遗传距离和地理因素间的关系（纬度、经度和海拔）作进一步分析，结果表明，地理位置（纬度和经度）是影响垂穗披碱草居群微卫星遗传差异的最重要因素（R=0．478；P＜0．05），其次是海拔（R=0．258；P＞0．05）。单一地理位置因素（纬度或经度）与遗传距离的相关性并不明显，但从单一地理位置因素与遗传距离的相关系数、可信度区间来看，纬度对遗传分化的影响程度大于经度。

Analysis of geographical conditions affected on genetic variation and relationship among populations of Elymus

Genetic variations and relationships of forty populations of nine species of Elymus L.from Qinghai-Tibetan Plateau and Mongolian Plateau of China were determined by microsatellite marker.Microsatellitedata indicatedthatgeneticsimilarityof forty Elymus populations ranged from 0.020 to 0.957.Genetic distance among these populations was related to their geographical origins.With Elymus nutans Griseb.as the model,the relationships of genetic distance and geographical location(latitude,longitude and altitude) were further analyzed using two and three dimensional Mantel test.The results showed that location(latitude and longitude) was the most important factor of influence on genetic difference(R=0.478;P<0.05),the next one was altitude(R=0.258;P>0.05). As for single environmental factor,considering relation coefficient and confidence interval(P>0.05),latitude had a greater influence on genetic differentiation than longitude.