REVERSIBILITY AND AGE OF AN ALLELE .1. MORANS INFINITELY MANY NEUTRAL ALLELES MODEL

A population of constant size is subjected to mutation, such that each mutant is of a new allelic type. The age of an allele, whose present frequency is known, is a random variable with distribution independent of the frequencies of other alleles. As a consequence of reversibility of the population process, the age of an allele, from the past to the present, has the same distribution as its time to extinction, from the present into the future.