Journal Article

Genome-wide association studies and genomic prediction of breeding values for calving performance and body conformation traits in Holstein cattle

Abo-Ismail, Mohammed K., Brito, Luiz F., Grossi, Daniela A., Plastow, Graham, Nayeri, Shadi, Sargolzaei, Mehdi, Miller, Stephen P., Moore, Steve S., Stothard, Paul, Schenkel, Flavio S.

2017

Overview

Background Our aim was to identify genomic regions via genome-wide association studies (GWAS) to improve the predictability of genetic merit in Holsteins for 10 calving and 28 body conformation traits. Animals were genotyped using the Illumina Bovine 50 K BeadChip and imputed to the Illumina BovineHD BeadChip (HD). GWAS were performed on 601,717 real and imputed single nucleotide polymorphism (SNP) genotypes using a single-SNP mixed linear model on 4841 Holstein bulls with breeding value predictions and followed by gene identification and in silico functional analyses. The association results were further validated using five scenarios with different numbers of SNPs. Results Seven hundred and eighty-two SNPs were significantly associated with calving performance at a genome-wise false discovery rate (FDR) of 5%. Most of these significant SNPs were on chromosomes 18 (71.9%), 17 (7.4%), 5 (6.8%) and 7 (2.4%) and mapped to 675 genes, among which 142 included at least one significant SNP and 532 were nearby one (100 kbp). For body conformation traits, 607 SNPs were significant at a genome-wise FDR of 5% and most of them were located on chromosomes 5 (30%), 18 (27%), 20 (13%), 6 (6%), 7 (5%), 14 (5%) and 13 (3%). SNP enrichment functional analyses for calving traits at a FDR of 1% suggested potential biological processes including musculoskeletal movement, meiotic cell cycle, oocyte maturation and skeletal muscle contraction. Furthermore, pathway analyses suggested potential pathways associated with calving performance traits including tight junction, oxytocin signaling, and MAPK signaling (P < 0.10). The prediction ability of the 1206 significant SNPs was between 78 and 83% of the prediction ability of the BovineSNP50 SNPs for calving performance traits and between 35 and 79% for body conformation traits. Conclusions Various SNPs that are significantly associated with calving performance are located within or nearby genes with potential roles in tight junction, oxytocin signaling, and MAPK signaling. Combining the significant SNPs or SNPs within or nearby gene(s) from the HD panel with the BovineSNP50 panel yielded a marginal increase in the accuracy of prediction of genomic estimated breeding values for all traits compared to the use of the BovineSNP50 panel alone.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Accuracy / Agriculture / Animal Genetics and Genomics / Animal lactation / Animals / Biological activity / Biomedical and Life Sciences / Body Composition - genetics / body conformation / Breeding / breeding value / bulls / Bulls (Cattle) / calving / Cattle - genetics / Cattle - growth & development / Cattle - physiology / Cattle industry / Cell cycle / Chromosomes / Chromosomes - genetics / Conformation / Dairy cattle / Dairy industry / Equilibrium / Evolutionary Biology / Expected values / Female / Fertility - genetics / Fetal Viability - genetics / Gametocytes / Gene polymorphism / Genes / genetic merit / Genetic research / Genome-wide association studies / genome-wide association study / Genome-Wide Association Study - methods / Genome-Wide Association Study - standards / Genomes / Genomics / genotype / Genotypes / genotyping / Health aspects / Holstein / Life Sciences / linear models / Livestock breeding / Male / MAP kinase / MAP Kinase Signaling System - genetics / Meiosis / Metabolic Networks and Pathways - genetics / Metabolism / Metabolites / Milk / mitogen-activated protein kinase / Muscle contraction / Muscles / Muscular function / Nucleotides / oocytes / Oxytocin / Oxytocin - genetics / Physiology / Polymorphism / Polymorphism, Single Nucleotide / prediction / Predictions / Quantitative Trait, Heritable / Research Article / Selective Breeding / Signal transduction / Signaling / Single-nucleotide polymorphism / Skeletal muscle / Software / tight junctions / Tight Junctions - genetics