Submitted to: International Conference on Animal Genetics
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 1998
Publication Date: N/A
Technical Abstract: The locus causing muscle hypertrophy (mh) has been previously assessed for birth and carcass traits. The objective of this study was to identify additional quantitative trait loci (QTL) segregating for economically important traits in two families segregating the mh locus. Two half sib families were developed from a Belgian Blue x MARC III (n=246) or a Piedmontese x Angus (n=209) sire. The effect of the mh locus was removed using information from six microsatellite markers on bovine chromosome 2. Selective genotyping was done on 96 animals from both families to identify genomic regions potentially associated with retail product yield (RPYD; %) and fat depth (FAT; cm), using a total of 150 genetic markers, informative in both families. Mean RPYD and FAT were 66.4 +/- .2% and .7 +/- .2 cm, respectively. When the entire family (n=246) and additional markers were included in the analysis of the family with Belgian Blue inheritance, a QTL Lsuggestive of linkage (nominal P=.0002) for marbling (MAR) was identified on bovine chromosome 27 (BTA27). The QTL for MAR (mean=500 +/- 3) is located at 58 cM from the most centromeric marker (BMS2168) on BTA27. The closest marker to the maximum F-statistic, BM17052 (59.2 cM), has an effect of 29.8 units (.59 residual standard deviations) between alternative alleles inherited from the sire. Individuals inheriting the Belgian Blue allele had more marbling compared with the MARC III allele. Putative QTL for RPYD, FAT, MAR, birth weight, rib-eye area, USDA yield grade, and Warner-Bratzler shear force at days 3 and 14 postmortem are also being evaluated in these families.