杉木遗传多态性与多基因位点遗传结构

在分析杉木16个群体的自由授粉种子胚乳蛋白质24个同功酶基因位点遗传多态性的基础上,进一步估计了遗传多态性与多基因位点之间的关系。研究结果表明:平均多态性位点占88.00％,每个位点平均有3个等位基因,期望杂合率为0.394;遗传多态性呈随机分布,但有7个位点等位基因频率与地理、气候因子相关;遗传多态性的6％归因于群体间的分化,94％属于群体内变异;16个群体中有15个存在双位点配子不平衡,大多数群体中明显存在高阶(两个基因位点以上)配子不平衡现象;配子不平衡与地理、气候因子之间相关呈随机分布。奠基者效应、群体的再分化、分布区内环境多样性以及2000多年人工栽培历史,均是产生和保持杉木群体遗传多样性及结构的重要因素。

GENETIC DIVERSITY AND MULTILOCUS STRUCTURE IN CHINESE FIR (CUNNINGHAMIA LANCEOLATA)

Open-pollinated seeds were assayed for allozyme polymorphisms at 24 loci to estimate genetic diversity and assess multilocus associations in 16 populations of Cunninghamia lanceolate (Lamb.) Hook in People's Republic of China. On average, percentage of polymorphic loci was 88. 00, number of al-leles per locus was 3. 00, and expected heterozygosity was 0. 394. Distribution of genetic diversity was random but allele frequency at seven loci correlated with geographic and climatic variables. Six percent of total gene diversity was attributed to among-population differentiation; 94% resided withinpopulations. Two-locus gametic disequilibria were found in 15 of 16 populations and highter order ga-metic disequilibria were significant in most populations. Correlations between gametic disequilibria andgeographic and climatic variables were random. Results suggested founde effect, population subdivision , occurrence across diverse environments and historical events from 2000 years of cultivation were factors in the generation and maintenance of genetic diversity and structure in this conifer.