Characterization of pro-opiomelanocortin gene variants and their effect on carcass traits in beef cattle

Abstract

Pro-opiomelanocortin is a prohormone that codes for many different peptides, some of which are involved in the appetite pathway. A single nucleotide polymorphism c.288C>T in pro-opiomelanocortin (POMC) was previously demonstrated to be associated with hot carcass weight (HCW) and shipping weight (Ship wt) in cattle. While developing a commercial real time PCR test for the POMC c.288C>T we identified a 12 bp deletion (POMC c.293_304delTTGGGGGCGCGG). The deletion results in the removal of four amino acids; valine, two glycine, and alanine. The deletion does not cause a frame shift. Both the POMC c.288C>T SNP and the deletion were genotyped in 386 crossbred steers, and evaluated for associations with carcass traits. The animals with one copy of the deletion had a significantly lower end-of-background rib-eye area (P=0.04) and carcass rib-eye area (P=0.03) when compared to animals without the deletion. A significant association with the POMC c.288C>T SNP was found with start of finishing weight (SOF WT); (P=0.04), HCW (P=0.02), average fat and grade fat (P=0.05), carcass rib-eye area (REA); (P=0.03) and marbling (P=0.02). These results suggest that it would be beneficial for beef producers to know both the deletion and the POMC c.288C>T SNP genotypes when making marketing and culling decisions.