EFFECTIVE POPULATION SIZES WITH MULTIPLE PATERNITY

While the concept of effective population size is of obvious applicabi lity to many questions in population genetics and conservation biology , its utility has suffered due to a lack of agreement among its variou s formulations. Often, mathematical formulations for effective sizes a pply restrictive assumptions that limit their applicability. Herein, e xpressions for effective sizes of populations that account for mating tactics, biases in sex ratios, and differential dispersal rates (among other parameters) are developed. Of primary interest is the influence of multiple paternity on the maintenance of genetic variation in a po pulation. In addition to the standard inbreeding and variance effectiv e sizes, intragroup (coancestral) and intergroup effective sizes also are developed. Expressions for effective sizes are developed for the b eginning of nonrandom gene exchanges (initial effective sizes), the tr ansition of gene correlations (instantaneous effective sizes), and the steady-state (asymptotic effective size). Results indicate that syste ms of mating that incorporate more than one male mate per female incre ase all effective sizes above those expected from polygyny and monogam y. Instantaneous and asymptotic sizes can be expressed relative to the fixation indices. The parameters presented herein can be utilized in models of effective sizes for the study of evolutionary biology and co nservation genetics.