AGB 121: Principles of Animal Genetics and Population Genetics (2+1)

SIB-ANALYSIS

• Half-sib analysis: The casual components of covariance are exactly similar to those of components of variance. Thus analysis of half-sib families the components of COV between sires estimates ¼ COV_A(XY) i.e. one-quarter of the COV of breeding values of two characters.
• For the estimation of correlation the components of variance of each character are also needed.
• Thus the between sire components of variance, σ²_S(X) and σ²_S(Y) estimate ¼ VAR_A(X) and ¼ VARA(Y) respectively for the trait-X and trait-Y. Therefore the rA is obtained as ¼ VAR_A(Y) respectively for the trait-X and trait-Y. Therefore the r_A is obtained as