Submitted to: John M. Airy Beef Cattle Symposium: Visions for Genetics and Breeding
Publication Type: Proceedings
Publication Acceptance Date: April 10, 2003
Publication Date: May 15, 2003
Citation: CASAS, E., SHACKELFORD, S.D., KEELE, J.W., STONE, R.T., KOOHMARAIE, M. QUANTITATIVE TRAIT LOCI FOR RETAIL PRODUCT YIELD AND MARBLING SCORE ON BOVINE CHROMOSOME 9. John M. Airy Beef Cattle Symposium: Visions for Genetics and Breeding. 2003. P. 128. Technical Abstract: A study to detect quantitative trait loci on bovine chromosome 9 affecting carcass composition and meat quality traits was pursued. Results from a genome-wide scan indicated the presence of quantitative trait loci on this chromosome. Thirteen microsatellite markers were genotyped on 547 progeny from a Brahman X Hereford sire mated to mostly Bos taurus crossbred dams. Traits analyzed were retail product yield (%) and marbling score (400 = slight**00, 500 = small**00). Quantitative trait loci were classified as significant when the expected number of false positives (ENFP) was less than .05 (F-statistic greater than 16.6), and suggestive when the ENFP was less than 1 (F-statistic between 10.0 and 16.59). A significant quantitative trait loci was detected for retail product yield (F= 20.6; ENFP= .008) at 71 cM from the beginning of the linkage group. Suggestive evidence for the presence of a quantitative trait loci for marbling score (F= 14.6; ENFP= .13) was detected at cM 67. The quantitative trait loci are resolved to regions of approximately 30 cM. The likelihood was greater than 1/10 of maximum between cM 63 and 92, and between cM 46 and 76, for retail product yield and marbling score, respectively. Animals with Brahman inheritance at the quantitative trait loci had 1.46 % more retail product yield and 21.7 units less in marbling score than animals with Hereford inheritance. The effect of the quantitative trait loci were .45 standard deviation units and .38 standard deviation units for retail product yield and marbling score, respectively. This is a case of genetic antagonism between the traits. This quantitative trait loci needs to be validated in additional target populations before being implemented in marker-assisted selection programs.