Mitochondrial DNA Heterogeneity in Tunisian Berbers

Authors

  • K. Fadhlaoui-Zid,

    1. Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie, Faculté des Sciences de Tunis, Université Tunis El Manar, 2092 Tunis, Tunisia
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    • *

      Both authors contributed equally to the present work

  • S. Plaza,

    1. Unitat de Biologia Evolutiva. Universitat Pompeu Fabra. Doctor Aiguader 80, 08003 Barcelona, Spain
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    • *

      Both authors contributed equally to the present work

  • F. Calafell,

    1. Unitat de Biologia Evolutiva. Universitat Pompeu Fabra. Doctor Aiguader 80, 08003 Barcelona, Spain
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  • M. Ben Amor,

    1. Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie, Faculté des Sciences de Tunis, Université Tunis El Manar, 2092 Tunis, Tunisia
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  • D. Comas,

    Corresponding author
    1. Unitat de Biologia Evolutiva. Universitat Pompeu Fabra. Doctor Aiguader 80, 08003 Barcelona, Spain
      **Correspondence: David Comas, Unitat de Biologia Evolutiva, Facultat de Ciències de la Salut i de la Vida, Universitat Pompeu Fabra, Doctor Aiguader 80, 08003 Barcelona, Spain. Tel: +34 93 542 28 02; Fax: +34 93 542 28 44. E-mail: david.comas@upf.edu
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  • A. Bennamar,

    1. Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie, Faculté des Sciences de Tunis, Université Tunis El Manar, 2092 Tunis, Tunisia
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  • El Gaaied

    1. Laboratoire de Génétique Moléculaire, Immunologie et Biotechnologie, Faculté des Sciences de Tunis, Université Tunis El Manar, 2092 Tunis, Tunisia
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**Correspondence: David Comas, Unitat de Biologia Evolutiva, Facultat de Ciències de la Salut i de la Vida, Universitat Pompeu Fabra, Doctor Aiguader 80, 08003 Barcelona, Spain. Tel: +34 93 542 28 02; Fax: +34 93 542 28 44. E-mail: david.comas@upf.edu

Summary

Berbers live in groups scattered across North Africa whose origins and genetic relationships with their neighbours are not well established. The first hypervariable segment of the mitochondrial DNA (mtDNA) control region was sequenced in a total of 155 individuals from three Tunisian Berber groups and compared to other North Africans. The mtDNA lineages found belong to a common set of mtDNA haplogroups already described in North Africa. Besides the autochthonous North African U6 haplogroup, a group of L3 lineages characterized by the transition at position 16041 seems to be restricted to North Africans, suggesting that an expansion of this group of lineages took place around 10500 years ago in North Africa, and spread to neighbouring populations. Principal components and the coordinate analyses show that some Berber groups (the Tuareg, the Mozabite, and the Chenini-Douiret) are outliers within the North African genetic landscape. This outlier position is consistent with an isolation process followed by genetic drift in haplotype frequencies, and with the high heterogeneity displayed by Berbers compared to Arab samples as shown in the AMOVA. Despite this Berber heterogeneity, no significant differences were found between Berber and Arab samples, suggesting that the Arabization was mainly a cultural process rather than a demographic replacement.

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