云南沟谷雨林建群种绒毛番龙眼居群的遗传多样性

Genetic diversity of Pometia tomentosa,a major constructive species of valley rainforest in Yunnan

  • 摘要: 【目的】了解云南特有的沟谷雨林主要建群种绒毛番龙眼居群的遗传多样性及遗传结构特征,为雨林植被恢复的采种规划和恢复效果评估提供重要参考。【方法】采用SSR分子标记技术,检测分析云南省西双版纳州和普洱市思茅区的绒毛番龙眼3个天然居群和1个人工居群共82个样本的SSR多态性,采用POPGENE v.1.32、GenAlEx 6.501和STRUCTURE 2.3.3等进行遗传多样性及遗传结构分析。【结果】19对SSR引物共检测到88个等位基因,每对引物平均4.632个,19个位点的Shannon’s信息指数(I)变化范围为0.264~1.687,平均为0.879;多态信息指数(PIC)变化范围为0.128~0.729,平均为0.422,期望杂合度(He)的变化范围为0.138~0.765,平均为0.473;4个居群I和He的均值分别为0.785,0.437。19个位点的遗传分化系数(FST)均值为0.069,基因流(Nm)的均值为3.363。STRUCTURE分析将绒毛番龙眼4个居群82个样本分为4个类群,基于遗传距离的UPGMA聚类显示4个居群聚为2个分支,菜阳河天然林居群、普文人工林居群和普文天然林居群聚为一支,勐养镇天然林居群单独为另一支。【结论】绒毛番龙眼的遗传多样性处于中等水平;居群间的遗传分化较低,遗传变异主要来源于居群内;建议特别关注居群内个体的选择和保护,在沟谷雨林植被恢复中设定天然居群多样性水平的恢复目标,并通过科学的采种规划实现这一目标。

     

    Abstract: 【Objective】Pometia tomentosa is a rare and precious local tree species in Yunnan Province of China and it is also one of the major constructive species for valley rainforests. Understanding the genetic diversity and genetic structure of Pometia tomentosa could provide a guide for a seed collecting strategy to effect vegetation restoration in valley rainforests.【Method】Four populations with a total of 82 samples of Pometia tomentosa from the Xishuangbanna prefecture were studied. Simple sequence repeat(SSR)molecular technique was used to detect polymorphism of allelic fragments. POPGENE,version,1.32 GenAIEx 6.501 and STRUCTURE 2.3.3 were used to analyze the genetic diversity and genetic structure of populations.【Result】Eighty-eight alleles were detected by 19 pairs of SSR primers with an average of 4.632 per pair. The range of Shannon's information index(I)was 0.264-1.687 with a mean of 0.879. Polymorphism information content(PIC)varied from 0.128 to 0.729 with a mean of 0.422,while expected heterozygosity(He)varied from 0.138 to 0.765 with a mean of 0.473. The average values of I and He for the 4 populations were 0.785 and 0.437 respectively. The average of genetic differentiation(FST)was 0.069 and gene flow(Nm)was 3.363,which means a relatively low genetic differentiation among the populations. The 4 populations were divided into 4 groups based on STRUCTURE analysis. UPGMA clustering indicated that the 4 populations were clustered into 2 branches,one of which consisted of a natural population in Caiyanghe,an artificial population in Puwen and a natural population in Puwen. The other branch contained only a natural population in Mengyang.【Conclusion】The genetic diversity of Pometia tomentosa is only medium at both the species and the population levels. Genetic variation comes mainly from within populations,so individuals within populations should be targeted for selection and conservation. In the recovery of valley rainforests,the genetic diversity of natural populations could be set as a target,which can be achieved by scientific planning of the seed collection

     

/

返回文章
返回