基于RAPD标记的叉蕊薯蓣和粉背薯蓣不同居群遗传多样性研究

Study on genetic diversity of different populations of Dioscorea collettii and D. collettii var. hypoglauca based on RAPD marker

采用RAPD分子标记技术对6个叉蕊薯蓣（Dioscorea collettii Hook. f.）居群及5个粉背薯蓣〔D. collettii var. hypoglauca （Palibin） C. T. Ting et al.〕居群的遗传多样性进行了分析,并基于遗传相似系数采用UPGMA法对11个居群进行了聚类分析。用14个寡聚核苷酸引物共扩增出170条带,其中多态性条带161条,多态性条带百分率高达94.71%;粉背薯蓣5个居群多态性条带百分率的变化幅度（81.25%~89.29%）略大于叉蕊薯蓣6个居群（82.00%~84.21%）。粉背薯蓣居群间的有效等位基因数（Ne）、Nei’s基因多样性指数（h）和Shannon多样性指数（I）分别为1.368 5、0.238 4和0.376 3,叉蕊薯蓣居群间的Ne、h和I分别为1.331 1、0.197 2和0.298 3;叉蕊薯蓣与粉背薯蓣间的基因分化系数（Gst）为0.122 8,基因流（Nm）为3.570 7。二者间的遗传相似系数为0.922 3,遗传距离为0.080 9;其中,粉背薯蓣江西庐山居群和叉蕊薯蓣云南丽江居群间的遗传距离最远,达0.693 1;叉蕊薯蓣云南蒙自和云南景洪居群间的遗传距离最近,仅0.219 4。根据聚类分析结果可将参试的11个居群分成4组,其中,所有的叉蕊薯蓣居群和粉背薯蓣浙江临安居群聚成第1组,粉背薯蓣重庆南川居群和湖南衡山居群聚为第2组,粉背薯蓣湖南永顺居群和江西庐山居群则各自独立成组。研究结果证明,叉蕊薯蓣和粉背薯蓣这2个类群之间为原变种和变种的关系,并存在着变种水平上的分化不完全。

Genetic diversity of six populations of Dioscorea collettii Hook.f.and five populations of D.collettii var.hypoglauca（Palibin） C.T.Ting et al.was studied by RAPD molecular marker,and cluster analysis of eleven populations was carried out by UPGMA method based on genetic similarity coefficient.The results show that 170 bands are amplified with fourteen oligonucleotide primers,in which there are 161 polymorphic bands with a percentage as high as 94.71%.The change range of polymorphic band percentage of five populations of D.collettii var.hypoglauca（81.25%-89.29%） is slightly higher than that of six populations of D.collettii（82.00%-84.21%）.The effective allele number（Ne）,Nei＇ s gene diversity index（h） and Shannon＇s diversity index（I） among D.collettii var.hypoglauca populations are 1.368 5,0.238 4 and 0.376 3,respectively,and those of D.collettii are 1.331 1,0.197 2 and 0.298 3,respectively.The gene differentiation coefficient（Gst） is 0.122 8 and gene flow（Nm） is 3.570 7 between D.collettii and D.collettii var.hypoglauca.The genetic similarity coefficient is 0.922 3 and the genetic distance is 0.080 9 between them,in which,the genetic distance between D.collettii var.hypolglauca population from Lushan of Jiangxi and D.collettii population from Lijiang of Yunnan is the farthest with a value of 0.693 1,while that between D.collettii populations from Mengzi and Jinghong of Yunnan is the nearest with a value of 0.219 4.According to cluster analysis result,the eleven populations can be divided into four groups.In which,all D.collettii populations and D.collettii var.hypoglauca population from Lin＇an of Zhejiang are clustered to the first group,D.collettii var.hypoglauca populations from Nanchuan of Chongqing and Hengshan of Hu＇nan are clustered to the second group,and D.collettii var.hypoglauca populations from Yongshun of Hu＇nan and Lushan of Jiangxi are respectively clustered to independently single groups.The results prove that the relationship of the two taxa is proto-variety and variety,but the incomplete differentiation in variant level still exists.