131 Genetic variants and haplotype combination in the bovine SH2B2 gene and their associations with molecular breeding for body size traits in Qinchuan cattle (Bos taurus)

Abstract

The Src homology 2 B 2 (SH2B2) gene regulates energy balance and body weight at least partially by enhancing Janus kinase-2 (JAK2)-mediated cytokine signalling, including leptin or GH signalling. Leptin is an adipose hormone that controls body weight. The objective of the current study was to evaluate the association between body measurement traits and SH2B2 gene polymorphisms. For this purpose, we selected four single-nucleotide polymorphisms (SNPs) in the SH2B2 gene, including two in intron 5 (A20545G and G20570A), one synonymous SNP (T20693C) in exon 6, and one in intron 8 (C24070A), and genotyped these through DNA sequencing in Qinchuan cattle. The general linear model (GLM) in SPSS 20.0 software (SPSS Inc.) was used for the association analysis between SNPs and selected traits of carcass quality. The SNPs in sample populations were in medium polymorphism level (0.250 < pic < 0.500). This association study indicated that the G20570A, T20693C, and C24070A were significantly (P < 0.05) associated with body length (BL) and chest circumference (CC) in Qinchuan cattle. In addition, the H4H3 and H5H5 diplotype were associated with significantly (P = 0.01) greater BL and rump length than was H4H2. Our investigation will not only extend understanding of genetic variations in the bovine SH2B2 gene but also provide useful information for marker-assisted selection in beef cattle breeding programs.