Abstract
This paper develops the biometrical aspects of traits having a direct and a maternal effect. Also the influence of a grand maternal effect is considered in conjunction with the direct and maternal effect. The theoretical expectations of several common covariances between relatives are derived from a general linear formulation that involves the relationships of the contributing individuals and the relevant genic variances and covariances. Copyright © 1972. American Society of Animal Science . Copyright 1972 by American Society of Animal Science.