Dominance is not necessary for heterosis: a two-locus model

Abstract

SummaryUnder a two-locus model with additive genes which combine multiplicatively to determine a quantitative trait, heterosis is generally observed in the F1 It is positive only if both frequencies of the best allele at each locus are not higher in the same parental population. In the F2, heterosis depends on the rate of recombination between the two loci. If linkage is tight, F1 superiority is nearly halved in the F2. But if the two genes are independent, heterosis is maintained in the F2 at the same level as in the F1.