Inbreeding coefficient and effective size for an X-linked locus in nonrandom mating populations

Abstract

Formulae are given for equilibrium inbreeding coefficients for an X-linked locus in infinite populations under partial full-sib, half-sib and parent-offspring matings, respectively. An exact recurrence equation for the inbreeding coefficient for an X-linked locus is derived for a finite population with equal numbers of males and females under partial full-sib mating. Following the approach of variance of change in gene frequency, two general equations for effective size for an X-linked locus are obtained. The equations consider an arbitrary distribution of family size, unequal numbers of males and females and nonrandom mating. For some special cases, the equations reduce to the simple expressions derived by previous authors. Comparisons are made between expressions for effective size for an X-linked locus and those for an autosomal locus. Some interesting conclusions are drawn from the analysis and discussed. © 1996 The Genetical Society of Great Britain.