A primary screen of the bovine genome for quantitative trait loci affecting carcass and growth traits.

Abstract

A primary genomic screen for quantitative trait loci (QTL) affecting carcass and growth traits was performed by genotyping 238 microsatellite markers on 185 out of 300 total progeny from a Bos indicus x Bos taurus sire mated to Bos taurus cows. The following traits were analyzed for QTL effects: birth weight (BWT), weaning weight (WW), yearling weight (YW), hot carcass weight (HCW), dressing percentage (DP), fat thickness (FT), marbling score (MAR), longissimus muscle area (LMA), rib bone (RibB), rib fat (RibF), and rib muscle (RibM), and the predicted whole carcass traits, retail product yield (RPYD), fat trim yield (FATYD), bone yield (BOYD), retail product weight (RPWT), fat weight (FATWT), and bone weight (BOWT). Data were analyzed by generating an F-statistic profile computed at 1-cM intervals for each chromosome by the regression of phenotype on the conditional probability of receiving the Brahman allele from the sire. There was compelling evidence for a QTL allele of Brahman origin affecting an increase in RibB and a decrease in DP on chromosome 5 (BTA5). Putative QTL at or just below the threshold for genome-wide significance were as follows: an increase in RPYD and component traits on BTA2 and BTA13, an increase in LMA on BTA14, and an increase in BWT on BTA1. Results provided represent a portion of our efforts to identify and characterize QTL affecting carcass and growth traits.

Search for quantitative trait loci affecting growth and carcass traits in a cross population of beef and dairy cattle1

“…Quantitative trait loci for growthrelated traits have also been identified in this chromosomal region (Davis et al, 1998;Stone et al, 1999;Kim et al, 2003;Machado et al, 2003). Quantitative trait loci affecting LM area and dressing percentage (Stone et al, 1999) are also coincident with the QTL we found upstream of DIK4782 for total saleable meat proportion and rib lean proportion.…”

“…The interval flanked by markers DIK4782 and IGF-1 harbors QTL reported for carcass yield (Mizoshita et al, 2004), fat depth and retail product yield (Casas et al, 2000), dressing percentage (Stone et al, 1999;MacNeil and Grosz, 2002), and rib bone and fat (Stone et al, 1999). Quantitative trait loci for growthrelated traits have also been identified in this chromosomal region (Davis et al, 1998;Stone et al, 1999;Kim et al, 2003;Machado et al, 2003). Quantitative trait loci affecting LM area and dressing percentage (Stone et al, 1999) are also coincident with the QTL we found upstream of DIK4782 for total saleable meat proportion and rib lean proportion.…”

“…The search for QTL affecting carcass yield and carcass composition in cattle has been mainly conducted by studying commercial half-sib families (Mizoshita et al, 2004;Mizoguchi et al, 2005) or experimental crosses [e.g., Bos indicus × Bos taurus (Stone et al, 1999;Casas et al, 2003) and Limousin × Wagyu cattle (Alexander et al, 2007)]. In the case of experimental cross populations, the QTL model used is based on the assumption that the founder lines are fixed for alternative alleles at the QTL (Haley et al, 1994).…”

QTL affecting body weight in a candidate region of cattle chromosome 5

“…Marker TEXAN15 is located at 4.2 cM of candidate gene IGF-1 and marker BMS1248 at 15.4 cM. QTLs influencing growth and other traits have been reported in this interval (Moody et al, 1996;Davis et al, 1998;Stone et al, 1999;Pereira, 2002). Deviations in the allelic frequencies of microsatellite TEXAN15 were reported in a Nellore population selected for weight, suggesting its association with a QTL affecting this trait (Merzel et al, 1998).…”

“…Bovine chromosome 5 harbors QTLs that influence milk production (Kalm et al, 1998), reproductivon (Kirkpatrick et al, 2000;Kappes et al, 2000;Lien et al, 2000) and growth and carcass traits (Moody et al, 1996;Davis et al, 1998;Stone et al, 1999;Casas et al, , 2002Pereira, 2002;Li et al, 2002). The location of some of these QTLs approaches the position of the IGF-1 (insulin-like growth factor) gene and, since IGF-1 plays a fundamental role in regulation growth and development, this gene is considered a strong candidate for the QTL effect.…”