Identification of growth trait related genes in a Yorkshire purebred pig population by genome-wide association studies.

Objective: The aim of this study is to identify genomic regions or genes controlling growth traits in pigs.

Methods: Using a panel of 54,148 single nucleotide polymorphisms (SNPs), we performed a genome-wide Association (GWA) study in 562 pure Yorshire pigs with four growth traits: average daily gain from 30 kg to 100 kg or 115 kg, and days to 100 kg or 115 kg. Fixed and random model Circulating Probability Unification method was used to identify the associations between 54,148 SNPs and these four traits. SNP annotations were performed through the data set from Ensembl. Bioinformatics analysis, including gene ontology analysis, pathway analysis and network analysis, was used to identify the candidate genes.

Results: We detected 6 significant and 12 suggestive SNPs, and identified 9 candidate genes in close proximity to them (suppressor of glucose by autophagy [], R-Spondin 2 [], mitogen activated protein kinase kinase 6 [], phospholipase C beta 1 [], rho GTPASE activating protein 24 [], cytoplasmic polyadenylation element binding protein 4 [], GLI family zinc finger 2 [], neuronal tyrosine-phosphorylated phosphoinositide-3-kinase adaptor 2 [], and zinc finger protein multitype 2 []). Gene ontology analysis and literature mining indicated that the candidate genes are involved in bone, muscle, fat, and lung development. Pathway analysis revealed that PLCB1 and MAP2K6 participate in the gonadotropin signaling pathway and suggests that these two genes contribute to growth at the onset of puberty.

Conclusion: Our results provide new clues for understanding the genetic mechanisms underlying growth traits, and may help improve these traits in future breeding programs.