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    濒危植物七子花种群间遗传分化的初步研究

    Primary study on genetic divergence within populations of Heptacodium miconioides

    • 摘要: 该文应用RAPD技术分析了9个七子花种群间的遗传分化。从70多个引物中筛选出清晰且多态性高的27个引物进行扩增,共检测到268个位点,其中多态位点163个,多态位点比率607%.平均每个引物扩增的DNA片段数约为10条。应用Jaccard公式计算9个种群的相似性,并以此为基础通过组间连接法作出9个种群遗传分化的树系图。结果显示9个种群分为3个分支:北山、植物园、大盘山和东白山种群组成一个分支;天台山和括苍山种群组成第二个分支;四明山种群单独一个分支。同时基于表型数据矩阵的PCA分析也支持上述的聚类结果。分析认为9个种群间的遗传分化程度与其间地理距离有一定的联系.最后,作者建议当前应采取以下两点保护措施:尽可能保护较多的种群数目;适当增加遗传分化较大的种群间的基因流。

       

      Abstract: Random amplified polymorphic DNA(RAPD)analysis was applied to the samples of Heptacodium miconioides from 9 main populations(No.1:Jiuquxi in Dapanshan ‚No.2:Huaxi in Dapanshan ‚No.3: Chachangshang in Dongbaishan ‚No.4:Beishan ‚No.5: Botanic Garden in Zhejiang Normal Univ . ‚No.6: Chachangxia in Dongbaishan ‚No.7: Tiantaishan ‚No.8:Kuocangshan ‚No.9: Si mingshan) . Twenty seven pri mers screened from 7 0ones yielded 268 RAPD bands which had 1 6 3polymorphic products and a total band rate of 60∙7%.The Jaccard coefficient was applied to compare the genetic si milarity of these 9populations based on the RAPD data .A dendrogram based on Jaccard coefficients was constructed by using the betweengroups linkage method . The dendrogramshows that these 9populations are clustered into three groups:No.1‚ No.2‚,No.3‚,No.4‚,No.5and No.6populations together;No.7and No.8populations in the second cluster;the SMS population(No . 9 ) alone in the last cluster . The dendrogramresult is also supported by a principal component analysis(PCA) of RAPD phenotypic data . The analysis indicates that the genetic variations within the nine populations are correlated with their geographical distance .Finally ‚the authors propose two approaches of conserving genetic diversity of H.miconioides populations in fragmented habitats based on its genetic structure and its biological characteristics.

       

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