|Thallman, Richard - Mark|
|Smith, Timothy - Tim|
Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/30/2004
Publication Date: 11/1/2004
Citation: Page, B.T., Casas, E., Quaas, R.L., Thallman, R.M., Wheeler, T.L., Shackelford, S.D., Koohmaraie, M., White, S.N., Bennett, G.L., Keele, J.W., Dikeman, M.E., Smith, T.P. Association of markers in the bovine capn1 gene with meat tenderness in large crossbred populations that sample influential industry sires. Journal of Animal Science. 82:3474-3481. 2004. Interpretive Summary: Genetic markers for the calcium-activated neutral protease gene (CAPN1) have been previously published and associated with meat tenderness, but in relatively artificial research populations with narrow genetic base. Our study demonstrates the predictive merit of these markers in commercial beef cattle, and indicates that the favorable alleles are present in all of the most popular Bos taurus beef breeds but at low to intermediate frequency. It also provides the basis for the most efficient selection by indicating the two-marker haplotype likely to be most consistently associated with a favorable functional allele. This provides the opportunity to use genetic markers to improve longissimus muscle tenderness. However, additional work is required to evaluate these markers in other breeds or to identify other more appropriate markers for those breeds; this is especially true for Bos indicus-influenced cattle.
Technical Abstract: Two previously identified single nucleotide polymorphism markers located within the micromolar calcium-activated neutral protease gene (CAPN1) were evaluated for association with variation in meat tenderness using one commercial sample of Simmental x Angus crossbred calves and one multibreed, crossbred research herd. The commercial sample included 362 animals sired by 23 registered Simmental bulls bred to unregistered Angus cows, and represents a relevant situation and current industry animals in which to test the predictive merit of the markers. The second sample was a research herd including 564 steers from the Germplasm Evaluation Cycle VII population at the U.S. Meat Animal Research Center, produced with semen from popular sires of the seven Bos taurus beef breeds with the most registrations in the U.S (Angus, Charolais, Gelbvieh, Hereford, Limousin, Red Angus, Simmental) on Angus, Hereford, and MARC III cows. These animals form a relatively outbred population that constitutes a stringent test of the predictive merit of the genetic markers, although small groups were half-sibs. Warner-Bratzler shear force measurements were used to determine tenderness phenotypes for all animals. The populations were genotyped for two markers that predict variation at amino acid positions 316 and 530 of the mu-calpain polypeptide, produced by the CAPN1 gene. Minor allele frequencies for markers 316 and 530 in the commercial sample were 0.17 and 0.37, respectively, and in the Cycle VII animals were 0.20 and 0.28, respectively. Both markers showed association with shear force in the commercial sample (P </= 0.04) and the Cycle VII population (P </= 0.02), supporting the hypothesis that they represent potential markers for selective breeding to improve meat tenderness in commercial populations of beef cattle in the U.S.