Genome-Wide Scan Identifies Selection Signatures in Chinese Wagyu Cattle Using a High-Density SNP Array

Abstract

Selective breeding can lead to genetic diversity and diverse phenotypes in farm animals. Analysis of the genomic regions under selection can provide important insights into the genetic basis of complex traits. In this study, a high-density SNP array was used for analysis of genome selection signatures in Chinese Wagyu cattle. In total, we obtained 478,903 SNPs and 24,820 no-overlap regions for |iHS| (integrated haplotype score) estimations. Under the threshold of the top 1%, 239 regions were finally identified as candidate selected regions and 162 candidate genes were found based on the UMD3.1 genome assembly. These genes were reported to be associated with fatty acids, such as Bos taurus nitric oxide synthase 1 adaptor protein (NOS1AP), Bos taurus hydroxysteroid 17-beta dehydrogenase 7 (HSD17B7), Bos taurus WD repeat domain 7 (WDR7), Bos taurus ELOVL fatty acid elongase 2 (ELOVL2), Bos taurus calpain 1 (CAPN1), Bos taurus parkin RBR E3 ubiquitin protein ligase (PRKN, also known as PARK2), Bos taurus mitogen-activated protein kinase kinase 6 (MAP2K6), meat quality, including Bos taurus ADAM metallopeptidase domain 12 (ADAM12), Bos taurus 5′-aminolevulinate synthase 1 (ALAS1), Bos taurus small integral membrane protein 13 (SMIM13) and Bos taurus potassium two pore domain channel subfamily K member 2 (KCNK2), growth, and developmental traits, such as Bos taurus insulin like growth factor 2 receptor (IGF2R), Bos taurus RAR related orphan receptor A (RORA), Bos taurus fibroblast growth factor 14 (FGF14), Bos taurus paired box 6 (PAX6) and Bos taurus LIM homeobox 6 (LHX6). In addition, we identified several genes that are associated with body size and weight, including Bos taurus sorting nexin 29 (SNX29), Bos taurus zinc finger imprinted 2 (ZIM2), Bos taurus family with sequence similarity 110 member A (FAM110A), immune system, including Bos taurus toll like receptor 9 (TLR9), Bos taurus TAFA chemokine like family member 1 (TAFA1), Bos taurus glutathione peroxidase 8 (putative) (GPX8), Bos taurus interleukin 5 (IL5), Bos taurus PR domain containing 9 (PRDM9), Bos taurus glutamate ionotropic receptor kainate type subunit 2 (GRIK2) and feed intake efficiency, Bos taurus sodium voltage-gated channel alpha subunit 9 (SCN9A), Bos taurus relaxin family peptide/INSL5 receptor 4 (RXFP4), Bos taurus RNA polymerase II associated protein 3 (RPAP3). Moreover, four GO terms of biological regulation (GO:0009987, GO:0008152) and metabolic process (GO:0003824, GO:0005488) were found based on these genes. In addition, we found that 232 candidate regions (~18 Mb) overlapped with the Quantitative trait loci (QTL)regions extracted from cattle QTLdb. Our findings imply that many genes were selected for important traits in Chinese Wagyu cattle. Moreover, these results can contribute to the understanding of the genetic basis of the studied traits during the formation of this population.