【摘要】 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(Kobresiahumilis)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)。更多还原

【Abstract】 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).更多还原