Abstract

Back fat thickness and meat tenderness are associated with a 526 T�A mutation in the exon 1 promoter region of the MyF-5 gene in Chinese Bos taurus

Qualitative trait loci (QTL) for growth and meat quality traits in cattle (Bos taurus) have been previously mapped to three chromosome regions, 0 to 30, 55 to 70, and 70 to 80 cM on chromosome 5. We evaluated the allele frequencies and gene-specific single nucleotide polymorphisms (SNPs) of bovine myogenic factor 5 (MyF-5) in the QTL regions and their associations with live weight and meat characteristics in indigenous Chinese cattle breeds. PCR-SSCP methodology showed a T>A mutation at 526 bp. Least square analysis revealed a significant association of this SNP with backfat thickness and meat tenderness (P < 0.05), while no significant association was found with live weight, loin eye height, loin eye area, rib area, or water holding capacity. Allele frequencies of MyF-5-A/B in the five breeds were 0.760/0.239, 0.752/0.247, 0.629/0.370, 0.715/0.284, and 0.750/0.250, for JiaXian red, Luxi, Nanyang, Qinchuan, and XiaNan crossbreed, respectively. The genotype distributions for these alleles in two of the Chinese cattle breeds (Luxi and Qinchuan) were not in Hardy-Weinberg equilibrium (P < 0.05); while those for the other three breeds (JiaXian red, Nanyang, and XiaNan) were in agreement with Hardy-Weinberg equilibrium (P > 0.05). The genotypic frequencies among all five cattle breeds showed moderate diversity (0.25 < polymorphism information content < 0.5). Based on our findings, we suggest that the MyF-5 gene influences back fat thickness and meat tenderness in Chinese Bos taurus. This SNP could be useful for markerassisted selection for meat quality traits in these cattle.

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