利用SSR分子标记分析秦岭冷杉自然居群的遗传多样性

利用10对SSR引物对濒危植物秦岭冷杉(Abies chensiensis)6个自然居群的120个个体进行了遗传多样性研究,旨在分析秦岭冷杉6个自然居群的遗传多样性、遗传结构及基因流变化.研究结果表明,120个个体在10个位点上共检测到149个等位基因,平均每个位点的等位基因数(A)为14.9,每个位点的有效等位基因数(e)为7.7,每个位点的平均预期杂合度(He)和平均观察杂合度(Ho)分别为0.841和0.243,Shannon多样性指数(Ⅰ)为2.13,自然居群杂合性基因多样度的比率(FsT)为6.7％,居群间的基因流(Nm)为3.45.利用Mantel检测到自然居群的遗传距离与地理距离间无显著相关性(r=0.490 6,P＞0.05).秦岭冷杉自然居群的遗传多样性水平较低,遗传变异主要存在于居群内部.结合研究数据、实地调查及相关资料,推测秦岭冷杉自然居群间基因流较原来增大可能是因为居群间发生了远交衰退.

Genetic Diversity in Natural Populations of Abies chensiensis Based on Nuclear Simple Sequence Repeat Markers

We analyzed the genetic diversity of 6 natural populations of Abies chensiensis （120 individuals） based on 10 simple sequence repeat markers to clarify genetic diversity, genetic structure and changes in gene flow in the populations. We detected 149 alleles in 10 microsatellite loci; the mean number of alleles per locus （A） was 14.9; the effective number of alleles per locus （Ne） was 7.7; the mean expected heterozygosity （He） was 0.841; and the mean observed heterozy- gosities per locus （Ho） was 0.243. The Shannon diversity index （I） was 2.13, with the proportion of genetic differentiation among populations （FsT） 6.7%. Gene flow between the populations （Nm） was 3.45. We found no significant correlation between genetic distance and geographic distance （r=0.490 6, P〉0.05）. Genetic diversity in the natural population of A. chensiensis was relatively low, with genetic variation mainly among populations. Our results, a field survey and related literature suggest that the gene flow between natural populations in A. chensiensis is higher than before, with perhaps distant hybridization between populations.