A genome-wide association study for natural antibodies measured in blood of Canadian Holstein cows

作者：B. de Klerk, Mehdi Emam, K.A. Thompson-Crispi, Mehdi Sargolzaei, J.J. van der Poel, Bonnie A. Mallard · 发表于：BMC Genomics · 年份：2018 · DOI：10.1186/s12864-018-5062-6 · 被引用次数：22 · 研究领域：Animal health and immunology、T-cell and B-cell Immunology、Milk Quality and Mastitis in Dairy Cows

BACKGROUND: Natural antibodies (NAb) are an important component of the innate immune system, and fight infections as a part of the first line defence. NAb are poly-reactive and can respond non-specifically to antigens. Therefore, NAb may be a key trait when evaluating an animal's potential natural disease resistance. Variation in NAb is caused by both genetic and environmental factors. In this study genetic parameters of NAb were estimated and a genome-wide association study (GWAS) was performed to gain further understanding on the genes that are responsible for the observed genetic variation of NAb in Canadian Holsteins. RESULTS: In total, blood samples of 1327 cows from 64 farms were studied. NAb binding to keyhole limpet hemocyanin (KLH) were determined via indirect ELISA. Immunoglobulin (Ig) isotypes, IgG and IgM, were evaluated. From the sample population, 925 cows were genotyped for 45,187 markers and each individual marker was tested to detect genetic variation in NAb levels. The relationships among animals was accounted for with genomic relationship. Results show heritabilities of 0.27 ± 0.064 (IgG) and 0.31 ± 0.065 (IgM). In total, 23 SNPs were found to be associated with IgG, but no SNPs were associated with IgM (FDR p-value < 0.05). The significant SNPs were located on autosomal chromosomes 1, 20 and 21 of the cow genome. Functional annotation analysis of the positional candidate genes revealed two sets of genes with biologically relevant functions related to NAb. ...