Edwards M D, Stuber C W, Wendel J F
Genetics. 1987 May;116(1):113-25. doi: 10.1093/genetics/116.1.113.
Individual genetic factors which underlie variation in quantitative traits of maize were investigated in each of two F2 populations by examining the mean trait expressions of genotypic classes at each of 17-20 segregating marker loci. It was demonstrated that the trait expression of marker locus classes could be interpreted in terms of genetic behavior at linked quantitative trait loci (QTLs). For each of 82 traits evaluated, QTLs were detected and located to genomic sites. The numbers of detected factors varied according to trait, with the average trait significantly influenced by almost two-thirds of the marked genomic sites. Most of the detected associations between marker loci and quantitative traits were highly significant, and could have been detected with fewer than the 1800-1900 plants evaluated in each population. The cumulative, simple effects of marker-linked regions of the genome explained between 8 and 40% of the phenotypic variation for a subset of 25 traits evaluated. Single marker loci accounted for between 0.3% and 16% of the phenotypic variation of traits. Individual plant heterozygosity, as measured by marker loci, was significantly associated with variation in many traits. The apparent types of gene action at the QTLs varied both among traits and between loci for given traits, although overdominance appeared frequently, especially for yield-related traits. The prevalence of apparent overdominance may reflect the effects of multiple QTLs within individual marker-linked regions, a situation which would tend to result in overestimation of dominance. Digenic epistasis did not appear to be important in determining the expression of the quantitative traits evaluated. Examination of the effects of marked regions on the expression of pairs of traits suggests that genomic regions vary in the direction and magnitudes of their effects on trait correlations, perhaps providing a means of selecting to dissociate some correlated traits. Marker-facilitated investigations appear to provide a powerful means of examining aspects of the genetic control of quantitative traits. Modifications of the methods employed herein will allow examination of the stability of individual gene effects in varying genetic backgrounds and environments.
通过检测17 - 20个分离标记位点处各基因型类别的平均性状表达，在两个F2群体中分别研究了构成玉米数量性状变异基础的个体遗传因素。结果表明，标记位点类别的性状表达可以根据连锁数量性状位点（QTL）的遗传行为来解释。对于评估的82个性状中的每一个，都检测到了QTL并将其定位到基因组位点。检测到的因子数量因性状而异，几乎三分之二的标记基因组位点对平均性状有显著影响。标记位点与数量性状之间检测到的大多数关联都非常显著，并且在每个群体中评估少于1800 - 1900株植物的情况下就可以检测到。基因组中与标记连锁区域的累积、简单效应解释了所评估的25个性状子集中8%至40%的表型变异。单个标记位点占性状表型变异的0.3%至16%。通过标记位点测量的个体植物杂合性与许多性状的变异显著相关。尽管超显性经常出现，特别是对于与产量相关的性状，但给定性状的QTL处明显的基因作用类型在性状之间以及位点之间都有所不同。明显的超显性普遍存在可能反映了单个标记连锁区域内多个QTL的效应，这种情况往往会导致对显性的高估。双基因上位性在决定所评估的数量性状的表达方面似乎并不重要。对标记区域对成对性状表达的影响的研究表明，基因组区域对性状相关性的影响方向和大小各不相同，这可能提供了一种选择来分离一些相关性状的方法。标记辅助研究似乎为研究数量性状的遗传控制方面提供了一种强大的手段。本文所采用方法的改进将允许检查个体基因效应在不同遗传背景和环境中的稳定性。
