A model of mutation appropriate to estimate the number of electrophoretically detectable alleles in a finite population

SUMMARY A new model of mutational production of alleles was proposed which may be appropriate to estimate the number of electrophoretically detectable alleles maintained in a finite population. The model assumes that the entire allelic states are expressed by integers (…, A −1 , A 0 , A 1 , …) and that if an allele changes state by mutation the change occurs in such a way that it moves either one step in the positive direction or one step in the negative direction (see also Fig. 1). It was shown that for this model the ‘effective’ number of selectively neutral alleles maintained in a population of the effective size N e under mutation rate υ per generation is given by When 4 N e υ is small, this differs little from the conventional formula by Kimura & Crow, i.e. n e = 1 + 4 N e υ, but it gives a much smaller estimate than this when 4 N e υ is large.