利用RAPD进行茶组植物遗传多样性和分子系统学分析

Genetic Polymorphism and Molecular Phylogeny Analysis of Section Thea Based on RAPD Markers

对张宏达系统山茶属茶组植物24种、变种的遗传多样性和分子系统学进行了RAPD分析。从冬梢中获得了高质量和高得率的基因组DNA, A260/A280平均为1.71,平均得率为331μg/g鲜重。从Operon技术公司的61个十聚体随机引物中筛选出15个用于茶组植物的RAPD扩增,在所扩增得到的107条可重现谱带中(平均7.1条/引物)有102条(平均6.8条/引物)是多态的,多态性程度是95.3%。每个引物扩增的谱带数在211条之间,相对多态性频度在0.04—0.96之间,不过总平均多态性频度只有0.30,在0.16—0.60之间。利用RAPD标记的Nei&Li氏系数和UPGMA法构建了茶组植物分子系统树,并进行SHMM主成分分析,结果均可将茶组植物分为“五室类群”和“三室类群”两大类。在UPGMA分子系统树上,两大类下可分别再分3个和2个亚类群。同时从遗传距离探讨了一些种的亲缘关系和分子进化。

The genetic polymorphism and molecular phylogeny of 24 species and varieties in section Thea genus Camellia were investigated. High quality and yield sample DNAs were isolated from winter shoots, the average A260/280 was 1.71 and the average yield was 331μg/g fresh base. Fifteen decamer oligonucleotide primers were selected from the 61 screened. A total of 102 polymorphic bands (6.8 polymorphisms/primer) out of 107 reproducible products (7.1 fragments/primer) were amplified from the selected 15 primers, corresponding to 95.3% polymorphism of the amplification bands. The relative polymorphic frequency ranged from 0.04 to 0.96. However, the general relative frequency of polymorphic was low with an average of 0.30, varying from 0.16 to 0.60. Molecular phylogenetic dendrogram of section Thea was constructed using UPGMA and based on Nei and Lis similarity coefficient from pairwise comparisons of RAPD data between 24 species and varieties. Principal coordinate analysis using SHMM method was also conducted. The species and varieties of section Thea could be divided into two groups, 5-locule ovary group and 3-locule ovary, and further be divided into 3 and 2 subgroups, respectively. The genetic relationship and molecular evolution tendency of some species were discussed from the genetic distance.