不同种源马尾松ISSR遗传结构及影响因素分析

应用ISSR分子标记技术,对来自广西、贵州3个种源的马尾松开展遗传多样性、遗传结构及遗传距离等研究。结果表明：从100条引物中筛选出12条引物,共扩增出92个条带,86条具有多态性。 POPGENE分析显示：马尾松群体水平上的Nei’ s基因多样性指数的变化范围为0.1824~0.2065,Shannon遗传多样性指数的变化范围为0.2818~0.3178,3个群体的多态性水平差异不大；物种水平上的多态性百分率为93.48％, Nei’ s基因多样性指数为0.2842,Shannon信息指数为0.4381；表明马尾松在物种水平上具有较高水平的遗传多样性。遗传结构分析显示：马尾松的基因分化系数( Gst)为0.3153,表明遗传变异主要来源于群体内；基因流Nm为1.0853,表明不同群体间存在一定的基因流动。 AMOVA分析显示：马尾松的遗传分化指数( Fst)为0.246( P＝0.001),表明群体间已出现明显的遗传分化。 UPGMA聚类和Mantel检测结果显示：每个群体内的个体均能很好地首先聚集为一个分支,群体间的遗传距离与地理距离之间存在显著相关性( r＝0.972, P＝0.001)。这说明马尾松在裸子植物界中具有较高水平的遗传多样性,遗传变异主要分布于群体内,群体间已出现了明显的遗传分化,这种分化并非由遗传漂变引起,可能与地理生境的差异有关。

Analysis of genetic structure and its related factors of Pinus massoniana from different populations by ISSR marker

ISSR markers were used to study the genetic diversity, genetic structure and genetic distance of three populations of Pinus massoniana from Guangxi Zhuang Autonomous Region and Guizhou provinces. Of the 100 primers screened,12 primers were selected and they generated 92 stable bands, among which 86 bands were polymorphic. The result of POPGENE indicated that Nei'' s gene diversities(h)at population level were from 0.182 4 to 0.206 5, Shannon''s information indexes(I)at population level were from 0.281 8 to 0.317 8, which suggested that the polymorphism level of three populations had small differences. At species level, the percentage of polymorphic bands(PPB)were 93.48%, Nei''s gene diversities(H)was 0. 284 2, Shannon''s information index(I)was 0.438 1. All those showed that P. massoniana had a higher genetic diversity at the species level. The analysis of genetic structure indicated that the average coefficient gene differentiation(Gst)was 0.315 3, which implied most of genetic variation appeared inner population. And the average number of the gene flow was 1.085 3, which indicated that there were a certain degree of gene exchanges between each population of P. massoniana. The result of AMOVA showed that the genetic differentiation index was 0.246(P=0.001), which indicated that the genetic differentiation was evident among different populations although there were gene exchanges between them. The UPGMA clustering and Mantel test showed that every individual inner population was first gathered for a branch. And there was significant correlation between the genetic distance and geographical distance among these three populations(r=0.972, P=0.001). Therefore, it was concluded from above that the P. massoniana was at a higher level of genetic diversity in gymnosperms; and the majority of genetic variation distributed within population; and the genetic differentiation from different populations of P. massoniana was hardly associated with the genetic drift but maybe caused by the difference from geographical and ecological environments. This study will provide theoretical reference and scientific basis for genetic improvement and plant introduction of P. massoniana.