岛屿地理隔离对红楠种群遗传结构的影响

利用简单重复序列间扩增(ISSR)分子标记对舟山群岛红楠(Machilus thunbergii)8个种群91个个体进行了遗传结构分析,9条随机引物扩增出可分析条带75条,多态位点百分比(PPL)为61.3%。POPGENE分析结果表明:红楠种群平均水平多态位点百分比(PPL)为52.3%,Nei′s基因多样度(HE)为0.186,较台湾岛红楠种群(PPL为71.1%)具有偏低的遗传多样性;而种群间遗传分化程度较高(GST=0.311)。地理距离与遗传距离具有显著相关性(r=0.655,P=96.1%),岛屿地理隔离对红楠种群间遗传分化产生显著影响。UP-GMA聚类分析表明:朱家尖岛与普陀岛红楠种群间遗传相似度较高,桃花岛与大猫岛可能存在较近的亲缘关系。基于舟山群岛红楠种群遗传结构分析,建议在其自然生长地实施就地保护的同时,建立红楠种质资源库,促进基因交流。

The Influence of Insular Geographical Isolation on Population Genetic Structure of Machilus thunbergii

Ninty-one individuals of eight populations of Machilus thunbergii collected from Zhoushan archipelago were examined by inter-simple sequence repeat(ISSR)markers to de-termine the genetic structure.A total of 75 discernible loci were obtained using 9 primers,of which 61.3%were polymorphic(P_(PL)=61.3%).As analyzed by POPOGENE,average values of precintage of bolymorphic loci(P_(PL)=52.3%)indicted that M.thunbergii had a reduction in genetic diversity compared with Taiwan populations.The value of differentiation(G_(ST)=(0.311))affirmed that M.thunbergii had high genetic differentiation among populations.The effect of geographical isolation had great influences and significant correlation was found between genetic distance and geographic distance(r=0.655,P=96.1%).UPGMA indicated that Putuo Island population showed a close relationship with Zhujiajian Island populations,Damao Island population and Taohua Island populations clustered in a clade.In order to maintain genetic diversity and resource utilization of M.thunbergii,management strategies were proposed that natural population should be protected in situ from human disturbance to facilitate its natural generation.Constructing germplasm resources and cultivating plants mutually collected from different populations are necessary to enhance the gene flow.