title: Islands inside an island: reproductive isolates on Jerba island.
abstract: Jerba Island, located in South Eastern Tunisia, is inhabited by four ethnic groups: Berbers, Arabs, sub-Saharans, and Jews. All live in distinct areas, although the Arabs are also distributed all over the island. The first Arab settlement was founded in the 7th century A.D., so co-existence with Berbers has lasted for more than a millennium. Religious and cultural differences have represented an obstacle to the intermixing of these groups, and among both Arabs and Berbers marriages usually occur between members from the same extended family. Using new mtDNA data and previously described Y-chromosome STR-defined haplotypes, we tested whether this reported inbreeding would be reflected in the differentiation between Berber and Arab communities. Concerning mtDNA, the Berber group presented a greater Eurasian contribution (87%), and, surprisingly, no U6 haplotypes were found; in contrast, the Arabs showed a larger contribution of sub-Saharan lineages (24%) and the U6 haplogroup amounted to 10%. Another source of evidence for the reproductive isolation of the two groups was revealed through the analysis of haplotype matching (both mtDNA and Y-chromosome), showing that matching probabilities between them is of the same order of magnitude of that observed when contrasting samples from different European countries.
authors.affiliation: Laboratory of Molecular Genetics, Immunology and Biotechnology, University of Sciences of Tunis, Tunis, Tunisia.
authors.forename: Besma Yacoubi
authors.initials: BY
authors.lastname: Loueslati
authors.forename: Lotfi
authors.initials: L
authors.lastname: Cherni
authors.forename: Houssein
authors.initials: H
authors.lastname: Khodjet-Elkhil
authors.forename: Hajer
authors.initials: H
authors.lastname: Ennafaa
authors.forename: Luísa
authors.initials: L
authors.lastname: Pereira
authors.forename: António
authors.initials: A
authors.lastname: Amorim
authors.forename: Farhat
authors.initials: F
authors.lastname: Ben Ayed
authors.forename: Amel
authors.initials: A
authors.lastname: Ben Ammar Elgaaied
mesh_terms: D018912:Arabs / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D005788:Gene Pool; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D006801:Humans; D008297:Male; D014416:Tunisia
chemical_list: D004272:DNA, Mitochondrial