FREQUENCY-DEPENDENT SELECTION, BENEFICIAL MUTATIONS, AND THE EVOLUTION OF SEX

This paper presents a mathematical model of a population in which mult iple alleles at a particular locus are maintained by frequency-depende nt selection. The results suggest that, if the population reproduces s exually, the benefit conferred on the population by beneficial mutatio ns at other loci will typically be much larger than if the population reproduces by asexual means. In part, this is true because, in asexual populations, beneficial mutations can produce suboptimal distribution s of the alleles that are subject to frequency-dependent selection. An other factor that produces an advantage for sex is that, in asexual po pulations, beneficial mutations that have achieved a high copy number may nevertheless be lost from the population. This is highly unlikely in sexual populations.