基于SSR标记的白栎天然居群遗传多样性分析

【目的】利用SSR分子标记,对白栎天然居群进行遗传多样性分析,为其种质资源的合理开发与保护提供指导。【方法】采用筛选出的SSR引物对3个群体进行遗传多样性与遗传结构研究,并计算遗传参数;基于个体间的遗传距离进行主成分分析,运用GenAlEx 6.5进行遗传距离与地理距离的相关性Mantel检验,软件Arlequin 用于分子方差分析,聚类分析采用MEGA 7中的UPGMA法;同时,使用Structure软件中的贝叶斯聚类算法探究群体遗传结构。【结果】6对SSR引物共检测到75个等位基因,平均有效等位基因数、观察杂合度和期望杂合度分别为7.16、0.70和 0.80,Shannon信息指数为2.05。AMOVA表明,群体内部的分子变异率高达97.41%,而群体之间的遗传变异仅为2.59%。黄山(YM)与天目山(TM)群体间的基因流为12.908,显著高于其他群体之间的交流水平,而二者间有着最近的遗传距离为0.272。贝叶斯法与UPGMA法聚类结果一致,表明来自YM与TM的个体亲缘关系更近。【结论】白栎具有较高的遗传多样性水平,且不同居群间的水平相当。YM和TM居群的基因交流最为密切,遗传分化不明显。白栎绝大部分遗传变异来源于群体内部,对于该物种的保护应减少不合理的人为开发行为,以原地保护为主,同时开展种质资源的收集与遗传改良工作。

Genetic diversity analysis among natural populations of Quercus fabri based on SSR markers

【Objective】This study used simple-sequence repeat(SSR)markers to analyze the genetic diversity on Quercus fabri Hance from natural populations.The study provides important advice concerning the reasonable exploitation and utilization of this resource.【Method】The analysis of the genetic diversity and genetic structure of Q.fabri was performed using screened SSR molecular markers.The genetic parameters were calculated and the principal coordinate analysis was applied based on the genetic distance among individuals.The analysis of molecular variance was conducted using Arlequin software.GenAlEx 6.5 was used to test the correlation between the genetic distance and geographic distance.MEGA 7 was used for the UPGMA phylogenetic analysis,and Structure was employed to perform the Bayesian clustering analysis to explore the genetic structure.【Result】A total of 75 alleles were detected from six markers.The average number of effective alleles,observed heterozygosity,and expected heterozygosity were 7.16,0.70 and 0.80,respectively.The Shannon’s information index was 2.05.AMOVA demonstrated that the genetic variation within populations(97.41%)accounted for the main percentage,with a negligible variation among populations(2.59%).The gene flow between Huangshan Mountain(YM)and Tianmushan Mountain(TM)was 12.908,which was much higher than that among other populations,and the genetic distance between the two populations was the closest(0.272).The results of the Bayesian clustering analysis were in accordance with the result of the UPGMA phylogenetic analysis,in that samples from the YM and TM populations had closer phylogenetic relationships.【Conclusion】There was a high and coincident level of genetic diversity among natural populations of Q.fabri.The genetic communication between YM and TM was the most frequent,and the genetic variation between these two spots was minor.For Q.fabri,the heritable variation within populations accounted for the majority of genetic variation.When collecting germplasm resources for the genetic improvement of this species,we should avoid unreasonable artificial exploitation.In addition,insitu conservation should be taken into consideration.