基于SSR标记的西藏光核桃群体遗传多样性和遗传结构分析  

Genetic Diversity and Population Structure of Amygdalus mira in the Tibet Plateau in China Based on SSR Markers

作　　者：包文泉[1] 乌云塔娜[2] 杜红岩[2] 李铁柱[2] 刘慧敏[2] 王淋[2] 白玉娥[1] Bao Wenquan;Wuyun Tana;Du Hongyan;Li Tiezhu;Liu Huimin;Wang Lin;Bai Yu＇ e(College of Forestry, Inner Mongolia Agricultural University Hohhot 010018;Non-Timber Forest Research and DevehJpment Center, Chinese Academy of Forestry Zhengzhou 450003)

机构地区：[1]内蒙古农业大学林学院,呼和浩特010018 [2]中国林业科学研究院经济林研究开发中心,郑州450003

出　　处：《林业科学》2018年第2期30-41,共12页Scientia Silvae Sinicae

基　　金：国家"十二五"科技支撑课题"仁用杏和巴旦杏高效生产研究与示范"(2013BAD14B02)

摘　　要：【目的】利用SSR标记深入研究西藏光核桃的遗传多样性及遗传结构,揭示其遗传结构与地理分布、海拔梯度等的相关性,为西藏光核桃资源的有效利用与科学保护提供理论依据。【方法】利用25对SSR引物,分析西藏地区21个光核桃天然群体420份个体的遗传多样性和遗传结构。应用Gen Al Ex 6.501、Arlequin v3.1、NTSYS pc version 2.10、STRUCTURE、STRUCTURE Harvester、CLUMP和Distruct等软件进行遗传参数估算、主坐标分析、遗传变异分析、聚类图构建及遗传结构分析。【结果】基于25个SSR分子标记的遗传多样性分析表明,西藏光核桃群体遗传多样性和近亲繁殖水平适中,其平均等位基因数(Na)、有效等位基因数(Ne)、期望杂合度(He)、观察杂合度(Ho)、Shannon’s信息指数(I)和近交系数(F)分别为3.8、2.5、0.52、0.44、0.95和0.17,其中,P17群体遗传多样性最高(Ne=4.7,He=0.63,Ho=0.56,I=1.57),而P18群体遗传多样性最低(Ne=1.7,He=0.30,Ho=0.22,I=0.49)。西藏光核桃的贝叶斯遗传结构分析(STRUCTURE)与遗传距离的主坐标分析(PCo A)、UPGMA聚类分析结果基本一致,均将供试420份光核桃个体划分为3个类群,其分组结果具有明显的地理区域特性。Mantel检测显示遗传距离与地理距离(r=0.50,P<0.01)、海拔梯度(r=0.61,P<0.01)呈显著正相关。分子方差分析(AMOVA)显示,16.3%的遗传变异来自群体间,群体间的遗传分化水平为中等,而大部分遗传变异(83.7%)来自群体内。【结论】西藏光核桃遗传多样性适中,群体间存在地理隔离效应和海拔梯度的遗传变异,其遗传分化程度较高,这可能源于西藏光核桃生境片段化、海拔梯度的影响以及山脉阻隔引起的地理隔离效应。西藏光核桃受人为干扰较严重,且个体间的近亲繁殖较频繁,若不及时采取保护措施,其遗传多样性将会逐渐降低。基于遗传结构分析,确定西藏光核桃3个保护单元,并建议限制人为活动【Objective】 In order to provide a theoretical basis for effective conservation and rational utilization of Amygdalus mira resources in Tibet,genetic diversity and population structure of 21 populations of A. mira were studied using SSR markers,and correlation between genetic structure and geographical distribution,altitudinal gradient were also analyzed.【Method】 A total of 420 individuals from 21 populations were assayed by 25 pairs of SSR primers. Genetic diversity parameters,principal coordinates analysis（ PCo A）,and analysis of molecular variance（ AMOVA） were carried out using Gen AIEx 6. 5 and Arlequin v3. 1 software. NTSYS software was used for cluster analysis based on the matrix of Nei’s genetic distance. STRUCTURE,STRUCTURE Harvester,CLUMP,and Distruct software were used to analyze genetic structure. 【Result】 Result showed that both genetic diversity and inbreeding were moderate within A. mira populations. The average number of alleles,effective number of alleles,expected heterozygosity,observed heterozygosity,Shannon’s information index,and inbreeding coefficient were 3. 8,2. 5,0. 52,0. 44,0. 95,and 0. 17,respectively.The highest level of genetic diversity was in the P17 population（ Ne= 4. 7,He= 0. 63,Ho= 0. 56,and I = 1. 57）,while the lowest was in the P18 population（ Ne= 1. 7,He= 0. 30,Ho= 0. 22,and I = 0. 49）. According to STRUCTURE,Principal coordinates analysis（ PCo A） and UPGMA cluster analysis,420 individuals could be divided into three genetic clusters,which were significantly correlated with geographic altitudes. Mantel test showed that the genetic distance among the populations was significantly correlated with geographic distance（ r = 0. 50,P 〈 0. 01） and geographic altitude（ r =0. 61,P 〈 0. 01）. AMOVA analysis showed that 16. 3% genetic variation was among the populations,which indicate that the level of genetic differentiation among population is moderate,while,a high genetic variation（ 83. 7%） was within populations.【Conclusion】 It was

关 键 词：光核桃 西藏 遗传多样性 遗传结构 SSR 

分 类 号：S718.46[农业科学—林学]