Lecture 3

Since an individual’s phenotype can be directly scored, the phenotypic variance VP can be estimated from measurements made directly on the random breeding population. In contrast, an individual’s breeding value cannot be observed directly, but rather must be inferred from the mean value of its offspring (or more generally using the phenotypic values of other known relatives). Thus estimates of VA require known collections of relatives. The most common situations (which we focus on here) are comparisons between parents and their offspring or comparisons among sibs. We can classify relatives as either ancestral or collateral, and we focus here on designs with just one type of relative. In a more general pedigree, information from both kinds of relatives is present. Ancestral relatives: e.g., parent and offspring