How much evolutionary advantage does sex confer?
In discussing the long term advantage of sex, Crow and Kimura (1965) and Maynard Smith (1971) have argued that the advantage of a reproductive system allowing recombination (sex) is greatest for large populations. However the validity of this conclusion depends upon the model used for evolution. We propose two simple models: the bootstrap model, where the number of loci at which favourable mutations may take place remains constant over long time periods; and the environment-led model, where evolution is at a constant rate dictated by the environment (and does not depend on the organism's ability to evolve). While the bootstrap model leads to conclusions similar to those mentioned above, the conclusions for environment-led evolution are the opposite: as the size of the population decreases the advantage for sex increases.
D005075:Biological Evolution; D008957:Models, Genetic; D009154:Mutation; D011995:Recombination, Genetic; D012098:Reproduction; D012723:Sex