基于重测序的陆地棉InDel标记开发与评价

碱基插入/缺失(InDel)是基因组中丰富的遗传变异形式。InDel以其密度高、易于基因型分型等优点成为分子标记开发的理想来源。本研究利用262份陆地棉品系重测序数据鉴定的InDel位点,在全基因组范围内设计了3206个InDel标记并挑选均匀分布的320个标记进行验证。320个标记筛选出87个多态性标记,多态性率为26.88%。利用多态性标记对不同地理来源的262份陆地棉种质资源进行基因分型,共检测到160个等位位点;多态性信息含量(PIC)为0.0836～0.3750,平均值为0.3073;基因多样性指数变异范围为0.0874～0.5000,平均值为0.3876,表明我国陆地棉遗传基础相对狭窄。群体结构分析将262份陆地棉品系大致划分为2个亚群,聚类分析和主成分分析的结果与之基本一致。采用混合线性模型(Mixed linear model)对6个纤维品质性状的关联分析检测到65个关联位点(P 0.01),各位点对表型变异贡献率为2.57%～8.12%。本研究旨在利用重测序数据开发全基因组范围的可用于凝胶检测的InDel标记,为棉花种质资源研究和分子标记辅助选择育种提供便捷工具。

Development and evaluation of InDel markers in cotton based on whole-genome re-sequencing data

Insertion and deletion (InDel) are abundant forms of genetic variation in the genome. InDel has been recognized as an ideal source for marker development due to its high-density distribution and genotyping efficiency. In this study, the whole genome re-sequencing data of 262 upland cotton accessions were applied to identify 3206 InDel markers, and 320 markers with uniform distribution across the genome were selected to be evaluated. Eighty-seven polymorphic markers were identified, accounting for 26.88% of screened markers. A total of 160 allelic loci were detected using the 87 polymorphic markers in the 262 upland cotton accessions with an average polymorphic information content (PIC) of 0.3073 (ranging from 0.0836 to 0.3750) and an average genetic diversity of 0.3876 (ranging from 0.0874 to 0.5000), indicating a relatively low genetic diversity. Population structure analysis revealed extensive admixture and identified two subgroups, clustering analysis and principal component analysis supported the subgroups identified by STRUCTURE. Association analysis were performed by MLM (Mixed linear model), and 65 marker loci were associated with fiber quality traits (P < 0.01), explaining 2.57%-8.12% of the phenotypic variation. Genome-wide and gel based InDel markers developed based on re-sequencing data in this study provide a facile tool for cotton germplasm resources research and molecular marker assisted selection breeding.