Wentzell Adam M, Boeye Ian, Zhang Zhiyong, Kliebenstein Daniel J
Genetics Graduate Group, University of California Davis, Davis, CA, USA.
PLoS Genet. 2008 Oct;4(10):e1000234. doi: 10.1371/journal.pgen.1000234. Epub 2008 Oct 24.
Most phenotypic variation present in natural populations is under polygenic control, largely determined by genetic variation at quantitative trait loci (QTLs). These genetic loci frequently interact with the environment, development, and each other, yet the importance of these interactions on the underlying genetic architecture of quantitative traits is not well characterized. To better study how epistasis and development may influence quantitative traits, we studied genetic variation in Arabidopsis glucosinolate activation using the moderately sized Bayreuth x Shahdara recombinant inbred population, in terms of number of lines. We identified QTLs for glucosinolate activation at three different developmental stages. Numerous QTLs showed developmental dependency, as well as a large epistatic network, centered on the previously cloned large-effect glucosinolate activation QTL, ESP. Analysis of Heterogeneous Inbred Families validated seven loci and all of the QTL x DPG (days post-germination) interactions tested, but was complicated by the extensive epistasis. A comparison of transcript accumulation data within 211 of these RILs showed an extensive overlap of gene expression QTLs for structural specifiers and their homologs with the identified glucosinolate activation loci. Finally, we were able to show that two of the QTLs are the result of whole-genome duplications of a glucosinolate activation gene cluster. These data reveal complex age-dependent regulation of structural outcomes and suggest that transcriptional regulation is associated with a significant portion of the underlying ontogenic variation and epistatic interactions in glucosinolate activation.
自然种群中存在的大多数表型变异受多基因控制，很大程度上由数量性状位点（QTL）的遗传变异决定。这些基因座经常与环境、发育以及彼此相互作用，然而这些相互作用对数量性状潜在遗传结构的重要性尚未得到充分表征。为了更好地研究上位性和发育如何影响数量性状，我们使用中等规模的拜罗伊特x沙达拉重组自交群体（就品系数量而言）研究了拟南芥硫代葡萄糖苷激活的遗传变异。我们在三个不同发育阶段鉴定了硫代葡萄糖苷激活的QTL。许多QTL表现出发育依赖性，以及一个以上述已克隆的大效应硫代葡萄糖苷激活QTL（ESP）为中心的大型上位性网络。异质近交家系分析验证了7个基因座以及所有测试的QTL x DPG（发芽后天数）相互作用，但由于广泛的上位性而变得复杂。对这些重组自交系中211个品系内转录本积累数据的比较表明，结构特异性因子及其同源物的基因表达QTL与已鉴定的硫代葡萄糖苷激活基因座有广泛重叠。最后，我们能够证明其中两个QTL是硫代葡萄糖苷激活基因簇全基因组重复的结果。这些数据揭示了结构结果复杂的年龄依赖性调控，并表明转录调控与硫代葡萄糖苷激活中很大一部分潜在的个体发育变异和上位性相互作用相关。
