Analysis of some two-locus systems for traits exhibiting continuous variation.

Some generalized two-locus, major-gene models for traits exhibiting continuous expression are investigated. Conditions of gametic equilibria are stated as functions of the parameters characterizing the within phenotypic-genotypic distributions. Selection is stabilizing in favor of an optimum phenotype. It is established that an increase in the phenotypic variance facilitates stability of a central polymorphic state with tighter linkage. Also, with increased phenotypic variance in an additive two-locus selection model, a HARDY-WEINBERG type of equilibrium will be less central. The rate of convergence, in this case, is slowed down with an augmented environmental background.