基于ITS序列分析钩苞大丁草九个居群的亲缘关系

该研究对我国西南地区钩苞大丁草(Gerbera delavayi)9个居群rDNA ITS序列进行PCR的扩增和检测序列,并以非洲菊(G.jamesonii)的ITS序列作为外类群,比较了序列之间的差异,同时分析了钩苞大丁草不同居群在地理距离与遗传距离之间的关系,构建了NJ系统发育树。结果表明:(1)钩苞大丁草9个居群的ITS序列全长介于600~700 bp之间,平均长度约为657 bp,其中,ITS1长度为243~246 bp,(G+C)含量为45.67%~46.80%之间,5.8S长度191~193 bp,(G+C)含量为58.60%~58.61%之间,ITS2长度为220~221 bp,(G+C)含量为57.00%~57.45%之间;ITS序列共有22个变异位点,ITS1序列(17个)、5.8S序列(2个)以及ITS2序列(3个)上均有变异。(2)地理距离与遗传距离有正相关(r2=0.652),序列间遗传分化距离为0.001 1~0.024 3,其中普洱居群与其他居群间遗传距离最大。(3)钩苞大丁草9个居群分成三个分支,普洱居群单独成支,丽江和洱源居群聚为一支,富源、武定、德昌、石林、新平和开远6个居群聚为一支。rDNA ITS序列可以用于钩苞大丁草群体遗传研究的分析,该研究结果为其保护性开发提供了参考依据。

Genetic relationship analysis of Gerbera delavayi from nine populations based on ITS sequences

Ribosomal DNA(rDNA)ITS of nine populations of Gerbera delavayi in Southwest China were amplified, sequenced and compared with G. jamesonii. The relationships of geographic distance and genetic distance of nine populations were studied. The NJ phylogenetic tree was also constructed. The results were as follows:(1)The whole length of ITS sequences of G. delavayi was 600-700 bp, the average length was 657 bp, the length of ITS1 was 243-246 bp,(G+C)amounted for 45.67%-46.80%, the length of 5.8S was 191-193 bp,(G+C)amounted for 58.60%-58.61%, the length of ITS2 was 220-221 bp,(G+C)amounted for 57.00%-57.45%. A total of 22 variable sites(ITS1, 7; 5.8S, 2 and ITS2, 3)were found.(2)The genetic distance had positive correlation with the geographic distance of G. delavayi(r2=0.652). The genetic differentiation distance was 0.001 1-0.024 3, among which the genetic distance between Pu''er and other population was the largest.(3)Nine populations were divided into three branches, in which Pu''er populations was separated as the first group. The second group contained Lijiang and Eryuan provenances. The other six populations(Fuyuan, Wuding, Dechang, Shilin, Xinping and Kaiyuan)were clustered together. RDNA ITS sequence analysis could be applied to study the population genetic of G. delavayi. The results provides reference for the protective development of G. delavayi.