Characterization of DGAT1 Allelic Effects in a Sample of North American Holstein Cattle |
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Authors: | Marcos Vinicius G Barbosa da Silva Richard M Thallman Erin E Connor Robert D Schnabel Curt P Van Tassell |
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Institution: | 1. Bovine Functional Genomics Laboratory, Agricultural Research Service, USDA , Beltsville, Maryland, USA;2. Embrapa Dairy Cattle, Juiz de Fora, Minas , Gerais, Brazil;3. U.S. Meat Animal Research Center, Agricultural Research Service, USDA , Clay Center, Nebraska, USA;4. Bovine Functional Genomics Laboratory, Agricultural Research Service, USDA , Beltsville, Maryland, USA;5. University of Missouri-Columbia, Animal Sciences Unit , Columbia, Missouri, USA |
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Abstract: | A putative causative mutation underlying a QTL was identified as a lysine to alanine non-conservative substitution at amino acid 232 of the gene encoding the acylCoA:diacylglycerol acyltransferase (DGAT1) protein. Our goal was to characterize the allelic substitution effects of this DGAT1 mutation in a large sample of Holstein bulls from North America. Statistically significant effects were identified for all of the milk production traits and somatic cell scores. Estimated average effects of substituting the lysine allele for the alanine variant on Holstein bull daughter yield deviations were ?81 kg, 3.7 kg, ?1.1 kg, 0.063%, 0.012%, and ?0.023 units for milk yield, fat yield, protein yield, fat component, protein component, and SCS, respectively. These estimates were largely in agreement with previous studies; however, the magnitudes of the estimates were much smaller in this study. Impacts on economic indices for net merit, cheese merit, and fluid merit were modest. Because of the strong antagonism between fat and protein yield and how those traits influence economic indices, selection for DGAT1 genotypes will likely not find widespread application in the U.S. |
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Keywords: | Dairy cattle Milk production Quantitative trait loci Substitution effect |
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