Submitted to: Animal Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/8/2003
Publication Date: 3/15/2004
Citation: CASAS, E., KEELE, J.W., SHACKELFORD, S.D., KOOHMARAIE, M., STONE, R.T. IDENTIFICATION OF QUANTITATIVE TRAIT LOCI FOR GROWTH AND CARCASS COMPOSITION IN CATTLE. ANIMAL GENETICS. 2004. 35:2-6. Interpretive Summary: The objective of the present study was to identify the location of genes affecting growth and carcass traits in cattle. We have utilized progeny from a Brahman x Angus sire to identify several chromosomal regions that influence these traits. Locations of genes affecting these traits were detected on chromosomes 1, 2, 3, 16, 17, 20, 21, and 26. Four of these chromosomes influenced more than one trait. Evidence supports the presence of genes affecting marbling on chromosome 2, while the evidence only suggests the presence of genes affecting growth and carcass composition traits in the remaining chromosomes. Locations of genes reported here are suitable to be investigated in other populations.
Technical Abstract: A genomic screening to detect quantitative trait loci affecting growth, carcass composition and meat quality traits was pursued. Two hundred nineteen microsatellite markers were genotyped on 176 of 620 progeny from a Brahman X Angus sire mated to mostly MARC III dams. Selective genotyping, based on retail product yield (percentage) and fat yield (percentage), was used to select individuals to be genotyped. Traits analyzed included in the study were birth weight (kg), hot carcass weight (kg), retail product yield, fat yield, marbling score (400 = slight**00, 500 = small**00), USDA yield grade, and estimated kidney, heart and pelvic fat (percentage). Quantitative trait loci were classified as significant when the expected number of false positives (ENFP) was less than .05 (F-statistic greater than 17.3), and suggestive when the ENFP was less than 1 (F-statistic between 10.2 and 17.29). A significant quantitative trait loci (F = 19; ENFP = .02) was detected for marbling score at centimorgan 54 on chromosome 2. Suggestive quantitative trait loci were detected for fat yield at centimorgan 50, for retail product yield at centimorgan 53, and for USDA yield grade at centimorgan 63 on chromosome 1, for marbling score at centimorgan 56, for retail product yield at centimorgan 70, and for estimated kidney, heart and pelvic fat at centimorgan 79 on chromosome 3, for marbling score at centimorgan 44, for hot carcass weight at centimorgan 49, and for estimated kidney, heart and pelvic fat at centimorgan 62 on chromosome 16, and for fat yield at centimorgan 35 on chromosome 17. Two suggestive quantitative trait loci for birth weight were identified, one at centimorgan 12 on chromosome 20 and the other at centimorgan 56 on chromosome 21. An additional suggestive quantitative trait loci was detected for retail product yield, for fat yield, and for USDA yield grade at centimorgan 26 on chromosome 26. These quantitative trait loci need to be assessed in other populations.