白木香遗传多样性研究

Studies on Genetic Diversity of Aquilaria sinensis

用ISSR分子标记技术对白木香(Aquilaria sinensis(Lour.)Gilg)的遗传多样性进行分析。结果表明,白木香物种水平的遗传多样性较高,而居群水平的遗传多样性相对较低,其中广东茂名居群的遗传多样性最高。白木香居群间存在较大的遗传分化,遗传分化系数GST=0.4425,表明居群内遗传分化大于居群间的分化。UPGMA聚类分析表明白木香分化为两个谱系,其中谱系Ⅰ由广东、福建、海南的5居群组成,谱系Ⅱ由广西、云南的3个居群组成。居群间的基因交流受到阻碍(Nm=0.6633<1),阻碍主要产生于两个谱系间,而谱系内部的居群间在较近的历史时期基因交流频繁(Nm分别为1.4382和1.2333),谱系分化的原因主要是地理因素,两谱系交界处有云开山脉等形成的天然屏障,阻碍物种的扩展和基因交流。

The genetic diversity of Aquilaria sinensis （Lour.） Gilg was investigated by using ISSR molecular markers. The results showed that there was high genetic diversity at the species level, and relatively low at the population level, in which the Maoming population （MM） had the highest genetic diversity. Significant genetic differentiation was found among populations of A. sinensis with Gsr = 0. 4425, it showed that the genetic differentiation within population was bigger than that between populations. The analyses of UPGMA and PCA revealed that 8 populations of A. sinensis were divided into two lineages, lineage I included 5 populations located in Guangdong （MM, GG and GZ）, Fujian （FJ） and Hainan （HN）, and lineage U comprised 3 populations in Guangxi （GX） and Yunnan （YX and YM）. At species level, the gene flow with Nm = 0.6633 〈 1 was very limited, which lead to high differentiation among populations. The limitation of gene flow mostly occurred between two lineages, while the gene flow was frequent within lineage with Nm 〉 1 in recent historical period. The main reason of genetic differentiation was geographical factors, which Yunkai Mountains located at borderline of two lineages hindered the gene flow between two lineages.