Association of SNPs in candidate genes with meat quality in crossbred cattle

Introduction Meat quality describes properties and perceptions of meat. For industry, cooking yield is also economically relevant. Many challenges face the meat industry and there is a need to identify genetically superior animals for these traits (Mullen et al., 2006). Tenderness, intramuscular fat (IMF) level and waterholding capacity are beef quality traits with moderate heritability, but which are difficult to improve by conventional selection. We aimed to test single nucleotide polymorphisms (SNPs) in candidate genes involved in pathways of relevance to meat quality, for association with these traits in crossbred Bos taurus cattle. Four published SNP in candidate genes were selected. Protein kinase AMP-activated gamma3subunit (PRKAG3) gene regulates AMPK activity in skeletal muscle and strongly influences glycogen metabolism. A SNP in this gene is influential on cook loss in pork (Milan et al., 2000, Ciobanu et al,. 2001). PRKAG3 is also expressed in bovine skeletal muscle and 7 SNP have been detected in 4 cattle breeds by Yu et al. (2005). Growth Hormone Receptor (GHR) exerts its effects on growth and metabolism by interacting with growth hormone. The GHR allele of an A/G polymorphism at position 257 in exon 10 was associated with higher drip loss values in beef aged 3 days (Di Stasio et al., 2005). Stearoyl-coA Desaturase (SCD) is a protein complex that is key in the synthesis of monounsaturated fatty acids (MUFA). The SCD allele at a SNP at position 702 in the open reading frame of the cDNA, contributed to higher MUFA percentage and lower melting point in IMF (Taniguchi et al., 2003). Finally, CAPN1 is a calcium-dependent, non-lysosomal cysteine protease – a number of SNP in CAPN1 have been associated with tenderness in a number of studies (e.g. Costello et al., 2007). The TT genotype of a SNP in CAPN1 intron 14 has been shown to be associated with higher percentage lean share in valuable cuts, compared to the CC genotype (Jusczuk-Kubiak et al., 2004).