On the modification of recombination with sex-dependent fitnesses and linkage.

According to the Reduction Principle, when a recombination-reducing allele is introduced near an equilibrium that depends on recombination, that allele will increase in frequency. If the allele increases the recombination rate, it will be expelled from the population. There are known cases where this principle fails. In this respect, an interesting question is what kind of two-sex viability regimes support a general Reduction Principle. In this paper, we construct a model of viabilities, due to two autosomal linked genes, which differ between the sexes, such that recombination is different in the sexes. A complete analysis is provided for the case where recombination is absent in one sex. It is proved that the Reduction Principle is still valid for recombination in the other sex.