Recombination dynamics and the fitness landscape

The evolution of a selectively neutral modifier of recombination is studied under different conditions of selection on the major genes. In a finite population a simulation study is carried out in which the phenotype is computed additively from the genotype at twenty genes. The fitness is taken to be a function of the phenotype and we show that when this function is very jagged, low recombination has a strong advantage. When the function is smooth and of the disruptive-selection kind, high recombination may be favored in both finite and very large populations. In a deterministic numerical study of disruptive selection on two loci it is shown that the evolution of recombination depends on the initial frequencies at the selected loci, on the exact shape of selection and on the strength of the selection. In general, when the selection is disruptive and very strong, it is possible to find conditions under which higher recombination will be favored.