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Title: Distribution and Location of Genetic Effects for Dairy Traits

Author
item Cole, John
item Vanraden, Paul
item O'CONNELL, J - UNIV OF MARYLAND
item Van Tassell, Curtis - Curt
item Sonstegard, Tad
item SCHNABEL, R - UNIV OF MISSOURI
item Wiggans, George

Submitted to: International Committee on Animal Recording(ICAR)
Publication Type: Proceedings
Publication Acceptance Date: 6/18/2008
Publication Date: 1/12/2009
Citation: Cole, J.B., Van Raden, P.M., O'Connell, J.R., Van Tassell, C.P., Sonstegard, T.S., Schnabel, R.D., Wiggans, G.R. 2009. Distribution and Location of Genetic Effects for Dairy Traits. International Committee on Animal Recording (ICAR). ICAR Tech Ser. 13:355–360. 2009.

Interpretive Summary: Genes affecting many dairy traits and total economic merit are fairly evenly distributed across all chromosomes in the bovine genome. A high-density scan using 39,314 SNP markers for 5,285 bulls confirmed two previously-known major genes on BTA 6 and 14 but revealed few other large effects. Markers on BTA 18 had large effects on calving ease, several conformation traits, longevity, and economic merit. Prediction accuracy was highest when models assumed that each marker had some effect on each trait, but allowed some markers to have large effects while most had small effects. Markers on the X chromosome were used to calculate sex-specific evaluations for males and females, but differences were small. The results validate the assumptions in quantitative genetic theory.

Technical Abstract: Genetic effects for many dairy traits and for total economic merit are fairly evenly distributed across all chromosomes. A high-density scan using 39,314 SNP markers for 5,285 bulls confirmed two previously-known major genes on BTA 6 and 14 but revealed few other large effects. Markers on BTA 18 had the largest affects on calving ease, several conformation traits, longevity, and total merit. Prediction accuracy was highest when priors assumed that each marker had an effect on each trait, but with a heavy-tailed distribution. Markers on the X chromosome were summed separately to provide different evaluations for male vs. female progeny, but differences were small. Results validate quantitative genetic assumptions.