Fundamental Theorem of Natural Selection

Abstract

FISHER'S fundamental theorem of natural selection has recently been discussed^1,2. Edwards² observes that the theorem V′ − V ≥ 0, where V and V′ represent, in successive discrete generations, the mean fitness at a single diallelic locus in a random mating diploid population, has already been proved by Moran³. He notes further that the more general result involving a multiple allelic system was actually established some years ago, and comments that the reason for this curiosity is that the validity of the theorem for two alleles was simply assumed to follow immediately from the work of Sewall Wright.