Corticotropin releasing hormone is a promising candidate gene for marbling and subcutaneous fat depth in beef cattle

The gene corticotropin releasing hormone (CRH) is mapped on bovine chromosome 14 (BTA14), where more than 30 fat-related quantitative trait loci (QTLs) have been reported in dairy and beef cattle. The gene product regulates secretion of adrenocorticotrophin hormone, the hypothalamic-pituitary-adrenal axis, and multiple hypothalamic functions; therefore, we hypothesized that CRH is a promising candidate gene for beef marbling score (BMS) and subcutaneous fat depth (SFD) in a Wagyu x Limousin F-2 population. Two pairs of primers were designed and a total of 5 single nucleotide polymorphisms (SNPs) were identified: g.9657C > T, c.10718G > C, c.10841G > A, c.10893A > C, and c.10936G > C (AAFC03076794.1). Among the 4 cSNPs, c. 10718G > C, c. 10841 G > A, and c. 10936G > C are missense mutations leading to amino acid changes from arginine to proline, from serine to asparagine, and from aspartic acid to histidine, respectively. These 5 SNPs were genotyped on similar to 250 F2 progeny, but only 4 were selected as tagging SNPs for association analysis because no historical recombination was observed between c. 10718G > C and c. 10893A > C. Statistical analysis showed that g.9657C > T, c.10718G > C, and c.10936G > C and their haplotypes had significant effects on SFD, but only c.10936G > C was significantly associated with BMS. The SNP in the promoter (g.9657C > T) led to gain/loss of a CpG site and 4 potential regulatory binding sites. Different haplotypes among the 4 cSNPs significantly affected mRNA secondary structures but were not associated with phenotypes. Overall, our results provide further evidence that CRH is a promising candidate gene for a concordant QTL related to lipid metabolism in mammals.