大连地区岛屿与大陆玉竹种群遗传多样性的ISSR分析

Genetic Diversity between Island and Mainland Natural Populations of Polygonatum odoratum in Dalian Area by ISSR

选取大连地区大陆与海岛共有植物玉竹为研究对象,采用ISSR分子标记技术对来自5个海岛和4个大陆种群的262个玉竹个体进行遗传多样性的比较和分析。从10个筛选出的ISSR引物扩增得到120个位点信息,其中多态性条带百分率为91.67%,Nei’s基因多样性指数(h)为0.346 0,Shannon信息指数(I)为0.510 8。其遗传分化系数(G_(st))为0.117 4,基因流(N_m)为3.758 5。研究结果表明玉竹天然种群的遗传多样性较为丰富,种群间基因交流较为频繁,遗传距离与地理距离具有一定的相关性。通过海岛与大陆种群遗传多样性的比对发现,海岛种群的遗传多样性略高于大陆种群,表明在孤立的生境和更为复杂的选择压力下,海岛玉竹种群可能会积累更多的遗传变异从而形成较高的遗传多样性水平。本文研究结果将为进一步探讨隔离生境中天然植物种群遗传进化规律提供证据。

With Polygonatum odoratum,a plant on both the mainland and islands in Dalian,we studied the genetic diversity of 262 P. odoratum from 5 islands and 4 mainland populations by ISSR molecular marker technology. Information of 120 loci was obtained by amplification of 10 ISSR primers that were screened out,where the percentage of polymorphic bands was 91. 67%,the gene diversity index of Nei＇s was 0. 346 0,and Shannon information index was 0. 510 8. Its genetic differentiation coefficient was 0. 117 4,and its gene flow was 3. 758 5. The genetic diversity of natural populations of P. odoratum was relatively rich with relatively frequent gene exchange among different populations,and its genetic distance had certain correlation with its geographic distance. By comparison between genetic diversity of populations from the mainland and islands,the genetic diversity of populations from islands was slightly higher than that from the mainland,indicating that under a more isolated ecological environment and more complicated selection pressure,populations of P.odoratum on islands might accumulate more genetic variation to form high levels of genetic diversity. Our results would provide evidence for further discussion on laws of genetic evolution of populations of natural plants in isolated ecological environments.