Resumo

BRANDA SICA, A. et al. Polymorphisms in two candidate genes for beef quality in Argentina. Arch. zootec. [online]. 2011, vol.60, n.231, pp.521-532. ISSN 1885-4494.  https://dx.doi.org/10.4321/S0004-05922011000300041.

Meat quality is a term used to describe a range of attributes of meat. It is determined by genetic and environmental factors (slaughter age, feeding and pre and post-slaughter management). The current tendency is to study the candidate genes in order to develop molecular markers, which might be used for marker-assisted selection. The objective of this work was to evaluate the effect of polymorphisms (SNP, single nucleotide polymorphisms) in candidate genes for tenderness and fat content in steers fattened in grazing beef production systems of Argentina. Molecular methods were designed to analyze the SNP 4751 (C/T) in bovine capn1 gene (large subunit of μcalpain), associated with tenderness and two polymorphisms (exon 8:G/A and intron 9:C/T) in bovine ppargc1a gene (peroxisome proliferatoractivated receptor gamma coactivator 1-alpha) with effect on fat content in cow milk and fiber type in pigs. Information of Warner-Bratzler shear force and fat content from 60 Brangus and 21 Angus steers was used in association studies. Tenderness of cooked meat was evaluated at 1.7 and 14 days post-mortem. A large proportion of animals were heterozygotes (CT) at SNP 4751. No differences were found between genotypes of this SNP for WBSF. A low frequency of homozygote TT was found at SNP on intron 9 of the ppargc1a gene. This SNP showed no significant effect on WBSF and fat content. Two new SNPs (G/A and T/C) were identified within exon 8 of the ppargc1a gene, by multiple alignment of DNA sequences obtained from 24 bulls of different breeds (Angus, Brangus, Brahman and Braford). One of them (G/ A) could be the cause of aminoacid substitution of serine by asparagine at position 364 of the protein. The A allele was not found in Angus. The SNP T/ C is a conservative substitution. It is important that Argentina generate information about factors affecting meat quality for optimizing the production and exportation of high quality beef.

Palavras-chave : Meat tenderness; Fat content; Molecular markers; SNP; capn1; ppargc1a.

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