广东省中山市五桂山土沉香空间遗传结构

Spatial Genetic Structure of Aquilaria sinensis in Wuguishan, Zhongshan, Guangdong Province

摘要:

为了解五桂山的土沉香（Aquilaria sinensis）种群空间遗传结构，利用18个微卫星位点对143株胸高直径大于5 cm的土沉香个体基因型进行了检测。结果表明，五桂山土沉香种群的观测杂合度和期望杂合度均为0.534；近交系数为0.000 1，说明五桂山土沉香遗传多样性并不低，且种群处于随机交配状况。空间遗传结构分析结果表明，五桂山土沉香缺乏空间遗传结构，不同遗传背景的个体相互混杂，导致相邻个体遗传差异较大。这可能是五桂山土沉香种群发育过程中自疏所致，也可能是这一地区土沉香为人工种植，而非自然发育形成而造成的。

Abstract:

In order to understand the spatial genetic structure of Aquilaria sinensis in Wuguishan, Zhongshan City, Guangdong Province, the genotypes of 143 individuals of A. sinensis with DBH (diameter at breast height) more than 5 cm were determined by using 18 microsatellite loci. The results showed that the observed heterozygosity and expected heterozygosity of A. sinensis population were all 0.534, and inbreeding coefficient was 0.000 1, which indicated that the genetic diversity of A. sinensis in Wuguishan was not low, and the whole population was under random mating situation. The genetic landscape shapes, spatial principal components analysis (sPCA) and spatial autocorrelation analysis showed A. sinensis in Wuguishan lack spatial genetic structure. The individuals with different genetic backgrounds mixed, so that the neighbors had high genetic differences. So, it was suggested that the self thinning and artificial planting of A. sinensis could be the two possible reasons.