利用SNP芯片构建我国冬油菜参试品种DNA指纹图谱

摘要

以 2016-2017 年度 187 份国家油菜参试品种及 2015-2016 年度 33份续试品种为材料, 利用油菜 60K Il-lumina Infinium SNP (single nucleotide polymorphism)芯片进行基因分型, 得到52157个SNP标记.按照分型为AA和BB频率不为0、最小基因型频率(minor freq)大于0.05、SNP得率(call freq)大于0.80、样品缺失率小于5%及分型明晰的要求筛选出5374个SNP标记.这些标记的PIC (polymorphism information content)均值为0.27, PIC值大于0.25的SNP标记占55.94%.其中有5143个SNP标记能对应到A1～A10、C1～C9连锁群上, 且比较全面地覆盖了油菜的基因组.用PowerMarker、MEGA等软件对224份样品的5374个标记分析, 结果显示: (1)设置8个品种重复2次点样对照, 得出 Infinium 芯片的技术误差为 0.36%, 与 Illumina 公司公布的 0.1%的技术误差十分接近. (2) NJ(Neighbor-joining)聚类分析中, 97.86%的区试品种的相似系数小于95%、87.88%的续试品种相似系数大于95%, 相似系数95%可作为品种特异性及一致性鉴定的阈值.这5374个 SNP标记在油菜全基因组上分布均匀、多态性高、区分度好, 可用于甘蓝型油菜品种特异性和一致性的鉴定分析及甘蓝型油菜品种DNA指纹图谱构建的研究.%Using the Brassica 60K Infinium SNP (single nucleotide polymorphism) array, a total of 52157 SNP markers were obtained by genotyping 33 annual test varieties in 2015–2016 and 187 varieties in 2016–2017. A total of 5374 high quality SNPs were retained after removing SNPs with AA or BB frequency = 0, main gene frequency ＜ 0.80, secondary gene frequency ＜ 0.05, sample loss rate ＞ 0.50, or SNPs that did not show clearly defined clusters. The mean PIC (polymorphism information content) value of selected 5374 markers was 0.27, SNPs with the PIC value ＞0.25 accounted for 55.94% of total number. Among 5374 SNPs, 5143 corresponded to the A1–A10 and C1–C9 linkage groups, and covered the rapeseed genome. We analyzed 5374 SNPs from 224 samples with softwares like PowerMarker and MEGA, etc. The technical error of the SNP array was 0.36%, when comparing two replicates of eight samples. It was close to the 0.1% technical error announced by Illumina. The NJ(Neighbor-joining) cluster analysis revealed that 97.86% of the tested varieties had a similarity coefficient of less than 93%, 87.88% renewed varieties had a similarity coefficient of greater than 95%, which could be further used as criteria for the varietal specificity and the annual consistency assessment. The 5374 SNP markers screened in this study were highly polymorphic and evenly distributed in the rapeseed genome, and could be used for future variety identification and the construction of DNA fingerprinting.