The inbreeding effective population number in dioecious populations.

The inbreeding effective population number in a dioecious population with discrete, nonoverlapping generations is investigated for both autosomal and X-linked loci. The recursion relations for the probabilities of genic identity, and the effective population numbers are analyzed and compared in two cases: (i) the offspring identified by sex in the calculation of the probability of common parentage and (ii) the offspring not so identified. Case i gives the correct evolution of the probabilities of identity, but case ii has been more widely studied and applied. A general symmetric framework that reduces the number of parameters is developed and used to examine a wide variety of models of panmixia and monogamy. Cases i and ii agree in many, but not all, models.