Predictions of X-linked inheritance for human characteristics

The conclusion reached by H. Thomas and W. Jamison (Developmental Review, 1981, 1, 274–283) that an observed sex-related difference in water-level task performance is due to an X-linked major gene raises the question of whether available data would be consistent with X-linkage predictions other than the one tested. Several predictions of X-linked inheritance for human characteristics are presented and discussed. It was concluded that although water-level task performance may involve a heritable component, the available data from seven independent studies reviewed by Thomas and Jamison are insufficient for determining the specific mode of genetic transmission.