青藏高原东部矮生嵩草遗传多样性的RAPD研究

基于随机扩增多态DNA（RAPD）方法分析了青藏高原东部矮生嵩草（Kobresia humilis）8个居群的遗传多样性及分化程度。14条随机引物共扩增出194个位点数，其中多态性片段168个。研究表明，矮生嵩草无论是在物种水平（多态条带比率PPB（％）为86．60％，Nei’s基因多样性（h）为0．2622，Shannon’s信息指数（I）为0．3983），还是在居群水平（PPB=62．65％，h=0．2126．I=0．3185），都具有较高的遗传多样性，居群的遗传多样性大小与生境有相关性。而且，用SPSS分析得出，8个居群的遗传多样性大小与海拔没有明显相关性。用AMOVA数据表明矮生嵩草的遗传变异主要分布在居群内（83．04％），居群间变异较小（16．96％）。遗传分化指数Gst也显示了相似的结果（0．1891）。从矮生嵩草8个居群的遗传距离和聚类分析发现，以及用NTSYS对矮生嵩草8个居群的的遗传距离矩阵与地理距离矩阵间的关系进行Mantel检测，其结果表明各居群间的遗传距离与地理距离之间没有明显相关性（r=0．37779，P=0．9718〉0．05）。

RAPD analysis of genetic diversity of Kobresia humilis along the eastern of QinghaiTibet Plateau of China

Kobresia humilis is a very important fine pasture and ecological grass in the Qinghai-Tibet Platau. In present study, the genetic diversity of K.humilis collected from eastern of the Qinghai-Tibet plateau in China, were investigated using RAPD markers. 194 loci were identified with 14 oligonucleotide primers, out of which 168 loci were polymorphic. K.humilis showed high genetic diversity: The percentage polymorphic loci (PPB%) was 86.60%, Nei's gene diversity (h) was 0.2622 and Shannon's information index (I) was 0.3983 at the species level; while the PPB% was 62.65%, h was 0.2126 and I was 0.3185, at the level of population. Moreover, the results showed that there was a relationship between the habitats and genetic diversity of K.humilis, but no correlation between the altitude and genetic diversity. AMOVA showed that most of the genetic variability (83.04%) resided among individuals within populations, whereas only 16.96% resided among populations. The Gst-values (0.1891) showed the similar result. Additionally, Nei's unbiased genetic distance matrix compared with a corresponding geographic distance matrix showed the two matrices were not significantly correlated (r=0.37779,p=0.9718>0.05).