Probability of identical monomorphism in related species

Abstract

SUMMARYA mathematical method for evaluating the probability that a locus is monomorphic for the same allele in related species is developed under the neutral mutation hypothesis. A formula for the proportion of identically monomorphic loci in related species is also worked out. The results of the application of this method toDrosophiladata do not support Prakash & Lewontin's (1968) contention that the strong association between gene arrangements (inversion chromosomes) and alleles at protein loci is evidence of coadaptation of genes in the inverted segment of chromosomes. Similarly, unlike Haigh & Maynard Smith's (1972) contention, the monomorphism of the haemoglobin α chain locus in man can be accommodated with the neutral mutation hypothesis without invoking the bottleneck effect.