Sasaki Shinji, Yoshinari Kanako, Uchiyama Katsuo, Takeda Masayuki, Kojima Takatoshi
National Livestock Breeding Center, Fukushima, Japan.
Anim Sci J. 2018 Nov;89(11):1533-1539. doi: 10.1111/asj.13110. Epub 2018 Sep 19.
Single nucleotide polymorphism (SNP) arrays are widely used for genetic and genomic analyses in cattle breeding. However, the relationship among sample genotyping efficiency (call rate per individual), accuracy of SNP genotypes, and DNA quality (integrity, concentration, and mixture of DNA, i.e., chimerism) remains unknown. We determined the effect of DNA quality on call rate per individual and accuracy of SNP genotypes using artificial DNA samples of various qualities. Integrity and concentration of DNA were less sensitive to call rate per individual and accuracy of genotyping in the SNP array. Chimerism strongly affected call rate per individual and accuracy of SNP genotypes. Artificial chimerism experiments showed that relative to unmixed DNA, the genotypic matching error (%) of mixed DNAs linearly increased with mix ratio, whereas the call rate per individual in some samples at 50% mix ratio was >0.95. However, individuals with higher chimerism were readily identified based on standard deviation of B-allele frequency (BAF) and BAF distribution across the genome from SNP array data. Thus, we effectively managed the balance by maximizing genotyping accuracy and minimizing the number of samples for re-genotyping by using quality control for combining call rate per individual with BAF.
单核苷酸多态性(SNP)阵列在牛育种的遗传和基因组分析中被广泛应用。然而,样本基因分型效率(个体的检出率)、SNP基因型准确性与DNA质量(完整性、浓度以及DNA混合物,即嵌合现象)之间的关系仍不明确。我们使用不同质量的人工DNA样本,确定了DNA质量对个体检出率和SNP基因型准确性的影响。DNA的完整性和浓度对SNP阵列中个体检出率和基因分型准确性的影响较小。嵌合现象对个体检出率和SNP基因型准确性有强烈影响。人工嵌合实验表明,相对于未混合的DNA,混合DNA的基因型匹配误差(%)随混合比例呈线性增加,而在50%混合比例时,部分样本的个体检出率>0.95。然而,基于SNP阵列数据中B等位基因频率(BAF)的标准差和全基因组BAF分布,嵌合程度较高的个体很容易被识别出来。因此,我们通过将个体检出率与BAF相结合进行质量控制,在最大化基因分型准确性和最小化重新基因分型样本数量之间有效地实现了平衡。