... of the trait in the i th line is V; , and the mean and the variance of the distribution of the variances of the lines are V and V(1; ),respectively. In each line, ... the evolution of the within-line phenotypic variance, since the magnitude of the special environment component is generally dependent on the degree of inbreeding. Fur-thermore, ... therefore segregatingloci affecting bristle number can be assumed to be initially in linkage equilibrium. Further-more, losses of lines during the period of inbreeding...