GENETIC ANALYSIS OF CONTINUOUS VARIATION - A COMPARISON OF EXPERIMENTAL DESIGNS APPLICABLE TO HUMAN DATA

The relative efficiencies of various experimental designs are compared for the genetical analysis of human behaviour. Particular attention is paid to the ability of the different designs to separate additive genetic variation from dominance variation. The utility of twins is investigated and it is shown that the relative number of twins need not be large for the statistical efficiency of the experiment to be optimal. The possibility of using foster‐siblings in the place of monozygotic twins reared apart is considered. It is demonstrated that a basic and efficient genetical analysis may be undertaken without recourse to monozygotic twins reared apart. The consequences for efficiency of limited availability of certain groups are investigated, and the method of the study illustrated with the aid of a worked example. 1969 The British Psychological Society