Sex-specific genetic differentiation and coalescence times: estimating sex-biased dispersal rates

Authors

  • Renaud Vitalis

    Corresponding author
    1. Laboratoire Génétique et Environnement, C.C. 065, Institut des Sciences de l’Évolution de Montpellier (UMR 5554), Université Montpellier II, F-34095 Montpellier Cedex 05, France,
    2. Station Biologique de la Tour du Valat, Le Sambuc, F-13200 Arles, France
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Renaud VITALIS. Laboratoire Génétique et Environnement, C.C. 065, Institut des Sciences de l’Évolution de Montpellier (UMR CNRS 5554), Université Montpellier II, Place Eugène Bataillon, F-34095 Montpellier Cedex 05, France. Fax: +33 4 67 14 36 22; E-mail: vitalis@isem.univ-montp2.fr

Abstract

I derive the equilibrium values of sex-specific FST parameters, in an island model for a dioecious species with sex-biased dispersal and binomial distribution of family size before dispersal (as assumed in a Wright–Fisher population). I show that FST may take different values among males and among females whenever dispersal is a trait conditioned on gender. This has not always been recognized, because some models assumed that genes are sampled before dispersal. In particular, the ratios of sex-specific FST parameters evaluated after dispersal over FST evaluated before dispersal are simple functions of sex-specific dispersal rates. Therefore, a simple moment-based estimator of sex-specific dispersal rate is proposed. This method is based on the comparison of FST estimated before and after dispersal and assumes equilibrium between migration and drift. I evaluate this method through stochastic simulations for a range of sex-specific dispersal rates and sampling effort (sample size, number of loci scored).

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