蜡梅天然群体遗传多样性的SRAP标记分析

 在蜡梅[Chim onanthus praecox (L.) Link ] 分布区内选取5个天然群体, 采用筛选出的7对SRAP (sequence-related amplified polymorphism) 引物进行遗传多样性分析。结果显示: 多态性条带百分率为23.4% , 多态位点比率( PPL ) 为83.41% , Nei's基因多样性指数(h) 为0121～0125 (均值为0.22) ,Shannonps信息指数( I) 为0.34, 群体分化系数(Gst) 为0.17, 群体间总的基因流的估算值Nm为2.40。AMOVA分析显示群体内方差分量的贡献率占79.89% , 而群体间方差分量的贡献率占20.11% , 区域间占32.39% , 区域内67.61%。Nei's (72) 群体遗传距离的UPGMA聚类分析显示群体间的遗传距离与群体的地理距离关系一致, Mantel分析相关系数为0.89。基于试验分析结果, 蜡梅种质资源保护和利用策略为在优先保护现有群体的基础上, 加强筛选和保存群体内的变异样本。

Genetic Diversity in Natural Populations of Chimonanthus praecox (L.) Link Revealed by SRAP Markers

The genetic diversity and genetic structure of natural populations of Chimonanthus praecox(L. ) L ink, were analyzed using Sequence-related Amp lified Polymorphism ( SRAP) markers. One hundred and fifty accessions from 5 natural populations were used in this study. Seven SRAP primer combinationsrevealed 170 legible bands of which 41 were polymorphic markers. The average proportion of polymorphic loci PPL was 83.41%. Gene diversity ( h) was from 0.21 to 0.25 ( average 0.22) , Shannonps Information index( I) was 0.34, coefficient of genetic differentiation (Gst) was 0.17 and the mean of gene flow estimated(Nm) was 2.40. The results of AMOVA indicated that the variance components within populations and among populations contributing to total genetic variance were 79189% and 20111%, among regions was 32.39% and within regions were 67.61%. There was obvious genetic differentiation among populations and among regions. UPGMA cluster analysis based on Nei's genetic distance indicated that the genetic distances wereclosely related to corresponding geographic distances among populations, 22wayMantel testMatrix correlation r was 0.89. Conservation and utilization strategies for the species should be therefore emphasized on conservingasmany as possible the existing populations, and selecting genetic diversitywithin populations considering the current conditions of severe population fragmentation and losses.