Abstract
As the first step in a study of the effects of linkage and epistasis on equilibrium frequencies of lethal genes, the necessary and sufficient conditions for stable equilibria of two interacting recessive lethals are worked out on the assumption of linkage equilibrium. The condition necessary for linkage equilibrium to be maintained permanently is also examined. The genetic variance in an equilibrium population is shown to be composed only of the dominance and dominance×dominance compoments.
