wheat expression level polymorphism study 39 genotypes 2 biological reps. Triticum aestivum

The use of statistical tools established for the genetic analysis of quantitative traits can be applied to gene expression data. Quantitative trait loci (QTL) analysis can associate expression of genes or groups of genes with particular genomic regions and thereby identify regions that play a role in the regulation of gene expression. A segregating population of 41 doubled haploid (DH) lines from the hard red spring wheat cross RL4452 x AC Domain was used. This population had previously been mapped with microsatellites and includes a full QTL analysis for agronomic and seed quality traits. Expression analysis from 5 day post anthesis developing seed was conducted on 39 of the 41 DH lines using the Affymetrix wheat array. Expression analysis of developing seeds from field grown material identified 1,327 sequences represented by Affymetrix probe sets whose expression varied significantly between genotypes of the population. A sub-set of 378 transcripts were identified that each mapped to a single chromosome interval illustrating that major expression QTLs can be found in wheat. Genomic regions corresponding to multiple expression QTLs were identified that were coincident with previous identified seed quality trait QTL. These regions may be important regulatory regions governing economically important traits. Comparison of expression mapping data with physical mapping for a sub-set of sequences showed that both cis and trans acting expression QTLs were present. Keywords: genetic differences, expression QTL Overall design: 39 genotypes of mapping population RL4452 x AC Domain with 2 biological replicates per genotype. Grown in the field in a lattice design

针对数量性状遗传分析所建立的统计工具，可应用于基因表达数据的研究。数量性状位点（Quantitative Trait Locus, QTL）分析能够将单个或多个基因的表达与特定基因组区域相关联，进而识别在基因表达调控中发挥功能的基因组区域。
本研究采用由硬红春小麦杂交组合RL4452 × AC Domain衍生的41份双单倍体（Doubled Haploid, DH）分离群体。该群体此前已通过微卫星标记完成遗传图谱构建，并针对农艺性状与种子品质性状开展了完整的QTL分析。
针对该群体中的39份DH系，利用Affymetrix小麦基因芯片对开花后5天的发育种子进行了表达谱分析。对田间种植材料的发育种子开展表达分析后，共鉴定出1327个由Affymetrix探针组（probe sets）代表的序列，其表达水平在该群体的不同基因型间存在显著差异。
进一步筛选得到378个转录本子集，每个转录本均定位至单个染色体区间，证实小麦中存在主效表达QTL。研究还鉴定到对应多个表达QTL的基因组区域，这些区域与此前已报道的种子品质性状QTL高度重合。此类区域或为调控经济重要性状的关键调控区域。
对部分序列的表达图谱与物理图谱进行比较后发现，同时存在顺式作用与反式作用的表达QTL。
关键词：遗传差异，表达QTL
整体实验设计：该定位群体RL4452 × AC Domain的39份基因型材料，每份设置2次生物学重复。采用格子设计（lattice design）于田间种植。