The effect of genetic linkage on the mean fitness of a population.

If many gene loci are kept in a segregating state by natural selection, the equilibrium frequencies of the genotypes in the population may be a function of the amount of recombination among the genes. It is shown that if the equilibrium vector of gametic frequencies is a continuous function of the set of recombination frequencies among genes, then the mean fitness of the population at equilibrium is a maximum in the absence of recombination. Thus, in general, restriction of recombination increases fitness.