岛屿地理隔离对山茶种群遗传结构的影响

利用简单重复序列间扩增(ISSR)分子标记对分布于我国浙江和山东的8个山茶种群共240个个体进行了遗传结构分析。结果表明:筛选出的20条引物扩增得到210条清晰条带,其中184条为多态性条带,多态位点百分率(PPB)为87.62%。经POPGENE1.32软件分析,山茶种群平均多态位点百分率(PPB)为68.99%,Nei’s基因多样性指数(HE)为0.256 9,Shannon信息指数(H)为0.377 9,种群遗传多样性较高。基因分化系数Gst=0.182 9,表明遗传变异主要存在于种群内个体间。地理距离与遗传距离具有显著相关性(r=0.856 7,P<0.05),岛屿地理隔离对山茶种群的遗传分化具有重要影响。UPGMA聚类表明:浙江5个山茶种群间的遗传相似度较高,山东青岛的植物园种群和五四广场种群可能移植自长门岩岛。我国野生山茶资源受人为破坏严重,建议在加强现有岛屿自然种群就地保护力度的同时,建立山茶种质资源库,促进基因交流。

The Influence of Insular Geographical Isolation on Population Genetic Structure of Camellia japonica

240 samples of Camellia japonica collected from 8 populations in Zhejiang Province and Qingdao City of Shangdong Province were analyzed by inter-simple sequence repeat(ISSR) markers to detect their genetic structure.210 discernible loci were obtained from all the populations using 20 primers.Of these loci,87.62% was polymorphic(PPB = 87.62%).The average percentage of polymorphic loci(PPB = 68.99%),Nei’s gene diversity(H E = 0.256 9) and Shannon’s Information Index(H = 0.377 9),estimated by POPGENE1.32,indicated that the C.japonica had higher level genetic diversity than many other insular plant species.The coefficient gene differentiation(Gst) was 0.182 9,indicating more variation was from the individuals of the populations.According to Mantel Test(r = 0.856 7,P < 0.05),geographical isolation had an important influence on genetic structure.UPGMA analysis revealed that there was a close relationship among 5 populations,the two populations from Qingdao might be translocated from Changmenyan Island.In order to maintain the genetic diversity and promote the resource utilization,the C.japonica natural population should be protected in situ and facilitate its natural generation.