濒危植物翅果油树种群的遗传多样性和遗传分化研究

Analysis on the Population Genetic Diversity of an Endangered Plant (Elaeagnus mollis) by SSR Markers

利用微卫星(SSR)标记对来自山西和陕西两省的7个翅果油树(Elaeagnus mollisDiels)种群进行遗传多样性和遗传结构研究。10对SSR标记共检测到126个位点,其中多态位点114个。在物种水平上,平均多态位点百分率为90.79%,有效等位基因数(Ne)、Nei基因多样性指数(H)和Shannon多样性指数(I)分别为1.6072、0.3166、0.4603;在种群水平上,多态位点百分率为61.99%,有效等位基因数(Ne)、Nei’s基因多样性指数(H)、Shannon多样性指数(I)分别为1.5445、0.2683、0.3815。遗传分化系数GST为0.2074,表明了翅果油树种群的遗传变异主要存在于种群内。基因流Nm为1.9111>1,说明种群间基因交流可以阻止由于遗传漂变导致的遗传分化。聚类结果表明,翅果油树种群间的遗传距离与地理距离有一定的相关性,经Mantel检验,种群的地理距离与遗传距离之间呈正相关,但未达到显著水平(p>0.05)。结果表明,遗传多样性水平与物种本身特性和不同干扰生境有关,濒危植物并不一定表现为遗传变异水平的降低。

Simple sequence repeat（SSR） markers were used to estimate the genetic structure and diversity of seven populations of Elaeagnus mollis,an endangered plant from the Shanxi and Shaanxi provinces,China.Ten pair primers generated a total of 126 reproducible and discernible loci,among which 114 were polymorphic.At a species level,the proportion of polymorphic loci was 90.79%.The effective number of alleles（Ne） was 1.6072,Nei＇s gene diversity index（H） was 0.3166,and the Shannon index（I） was 0.4603.At a population level,the proportion of polymorphic loci was 61.99%,Ne=1.5445,H=0.2683,and I=0.3815.The coefficient of gene differentiation（Gst=0.2074） showed greater genetic variations occurred within the population than among populations.Gene flow（Nm） was 1.91111,which showed that gene interflow occurred among populations,and that genetic differentiation was prevented due to genetic drift.Cluster analysis showed a certain correlation between genetic distance and geographic distance.Mantel test showed a positive correlation between geographic distance and genetic distance,but did not reach a significant level（p0.05）.The results showed that genetic diversity was related to species traits and habitat disturbance.The endangered plants did not necessarily display a lower level of genetic variation.