title: Mitochondrial DNA and Y-chromosome microstructure in Tunisia.
abstract: Mitochondrial DNA (mtDNA) and Y-chromosome variation has been studied in Bou Omrane and Bou Saâd, two Tunisian Berber populations. In spite of their close geographic proximity, genetic distances between them were high and significant with both uniparental markers. A global analysis, including all previously studied Tunisian samples, confirmed the existence of a high female and male population structure in this country. Analyses of molecular variance analysis evidenced that this differentiation was not attributable to ethnic differences. Mantel test showed that, in all cases, Y-chromosome haplotypic distances correlated poorly with geography, whereas after excluding the more isolated samples of Bou Omrane and Bou Saâd, the mtDNA pattern of variation is significantly correlated with geography. Congruently, the N(m) ratio of males versus females pointed to a significant excess of female migration rate across localities, which could be explained by patrilocality, a common marriage system in rural Tunisia. In addition, it has been observed that cultural isolation in rural communities promotes, by the effect of genetic drift, stronger loss of diversity and larger genetic differentiation levels than those observed in urban areas as deduced from comparisons of their respective mean genetic diversity and their respective mean genetic distances among populations. It is likely that the permanent exodus from rural to urban areas will have important repercussions in the future genetic structure of this country.
authors.affiliation: Department of Biology, Laboratory of Genetics, Immunology and Human Pathology, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia. ennafaahajer@yahoo.fr
authors.forename: Hajer
authors.initials: H
authors.lastname: Ennafaa
authors.forename: Rosa
authors.initials: R
authors.lastname: Fregel
authors.forename: Houssein
authors.initials: H
authors.lastname: Khodjet-El-Khil
authors.forename: Ana M
authors.initials: AM
authors.lastname: González
authors.forename: Hejer Abdallah El
authors.initials: HA
authors.lastname: Mahmoudi
authors.forename: Vicente M
authors.initials: VM
authors.lastname: Cabrera
authors.forename: José M
authors.initials: JM
authors.lastname: Larruga
authors.forename: Amel
authors.initials: A
authors.lastname: Benammar-Elgaaïed
mesh_terms: D044383:Black People / Q000235:genetics*; D041322:Chromosomes, Human, Y / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D014416:Tunisia
chemical_list: D004272:DNA, Mitochondrial