1. ¹Eco-anthropologie et Ethnobiologie, UMR5145 Department Hommes Natures Societes, MNHN, Paris, France
2. ²Evolution et Diversit Biologique, Universit Paul Sabatier UMR 5174, Toulouse, France
3. ³Centre d'Anthropologie, UMR 8555 CNRS, Toulouse, France

Correspondence: P Balaresque, Department of Genetics, Adrian Building, University of Leicester, University Road, Leicester LE2 7RH, UK. E-mail: plb7@le.ac.uk

Received 2 November 2004; Accepted 7 November 2005; Published online 4 January 2006.

Abstract

Homologous markers on the sex-specific regions of the X- and Y-chromosomes are differentially inherited through males and females, and have similar molecular characteristics. They may therefore be useful as a complement to the comparison of mtDNA and Y-chromosomal haplotypes for estimating sex-specific processes shaping human population structure. To test this idea, we analyzed XY-homologous microsatellite diversity in 33 human populations from Africa, Asia and Europe. Interpopulation comparisons suggest that the generally discordant pattern of genetic variation observed for X- and Y-linked markers could be an outcome of sex-specific migration processes (m_females/m_males3) or sex-specific demographic processes (N_females/N_males11) or a combination of both. However, intrapopulation diversity estimated by the X/Y ratio Watterson estimator (_H(Y)/_H(X)) suggests that the scenarios required to explain the global genetic variation of XY-homologous markers are many and complex, and that the sex-specific processes (effective population size and migration rate) shaping human population structures are likely to be specific to each population under study. XY-homologous markers provide an insight into the genuine complexity of sex-specific processes, and their further exploitation in human population studies seems worthwhile.