Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Proceedings
Publication Acceptance Date: May 9, 2010
Publication Date: August 1, 2010
Citation: Bennett, G.L., Shackelford, S.D., Wheeler, T.L., King, D.A., Casas, E., Smith, T.P. 2010. Application of marker selection to enhance estimation of genetic effects and gene interaction in cattle. Proceedings, 9th World Congress on Genetics Applied to Livestock Production, Leipzig, Germany. August 1-6, 2010. CD-ROM Communication No. 0286. Interpretive Summary: Genetic markers are increasingly being used in beef cattle to increase the rate of genetic change for economically important traits. Multi-year selection for important genetic markers in experimental herds can improve estimates of markers effects. These selected herds can more efficiently answer questions about whether two copies of a marker are twice as effective as a single copy, or whether the effect of one marker depends on another marker. An experimental herd of beef cattle was selected for intermediate frequencies of markers in two different genes previously reported to affect muscle growth and meat tenderness. The marker for muscle growth increased meat yield and muscle size, decreased fat in the carcass and in the muscle, and did not change carcass weight. Two copies of this marker had twice the effect of one copy for meat, muscle and fat. Results for the other marker were not conclusive and will require additional data. When completed, breeders and their genetic service providers will have better information on how to use these genetic markers.
Technical Abstract: Selection on important genetic markers can improve estimates of additive and dominance association effects. A composite population of beef cattle was selected for intermediate frequencies of myostatin (GDF8) F94L and µ-calpain (CAPN1) polymorphisms. Important additive associations of the GDF8 locus with carcass yield, muscle, and fat were estimated in 97 steers. Additive associations were 0.7-0.9 times residual standard deviations for these traits. Results showed no evidence of important dominance effects associated with F94L for these traits. Selection for CAPN1 to improve estimates of haplotypes was not as successful because complicating factors in determining haplotypes slowed selection response.