A Note on the Power Provided by Sibships of Sizes 2, 3, and 4 in Genetic Covariance Modeling of a Codominant QTL.

The contribution of size 3 and size 4 sibships to power in covariance structure modeling of a codominant QTL is investigated. Power calculations are based on the noncentral chi-square distribution. Sixteen sets of parameter values are considered. Results indicate that size 3 and size 4 sibships provided large increases in power over size 2 sibships. On average a size 3 (4) sibship is 3 (6 to 7) times as informative as a size 2 sibship. The increase in power does not depend on the specific effects sizes of the independent variables in the model. These findings extend results presented by Fulker... Mehr ...