Experimental Design in the Evaluation of Genetic Parameters

Rather surprisingly, there appears to be no discussion in the literature of the best design for the estimation of intraclass correlations and, consequently, in the context of quantitative genetics, of heritabilities. Put rather more specifically, if we have facilities for the measurement of a certain number of objects with a hierarchical classification, what is the most efficient group size for the estimation of intra-group correlations? We shall be dealing here with the situation in which, in any experiment, all groups are of the same size. As more work is now being done on the quantitative genetics of laboratory animals, in which the family structure is rather more under the experimenter's control than in farm animals, it seemed valuable to put these results on paper.