Polymorphisms of the bovine MC3R gene and their associations with body measurement traits and meat quality traits in Qinchuan cattle

The melanocortin 3 receptor (MC3R) gene, which belongs to the rhodopsin-like family A of the G protein-coupled receptor family, plays a crucial role in feed efficiency and energy homeostasis. The aim of this study was to examine associations between bovine MC3R gene polymorphisms and body measurement traits (BMTs) and meat quality traits (MQTs). We identified three synonymous mutations (T429C, T537C, and T663C) in exon 1 of the MC3R gene in Chinese Qinchuan beef cattle (N = 271) by sequencing. D' and r(2) values revealed that these three SNPs were in strong linkage disequilibrium (LD) (r(2) > 0.33); the T429C and T537C SNPs were in complete LD (D' = 1 and r(2) = 1). Association analyses revealed that the SNPs were significantly associated with BMTs and MQTs in Qinchuan cattle. Individuals with the wild homozygotic genotypes g.TTTT and g.TT had significantly higher values of chest depth, heart girth, back fat thickness, intramuscular fat content, and loin muscle area than the mutant heterozygotic genotypes g.TCTC and g.TC. These results suggest that the MC3R gene affects MQTs in Qinchuan cattle, and that it may be a good candidate gene for marker-assisted selection.