Article

European Journal of Human Genetics (2011) 19, 89–94; doi:10.1038/ejhg.2010.128; published online 11 August 2010

Genetic diversity on the Comoros Islands shows early seafaring as major determinant of human biocultural evolution in the Western Indian Ocean

Said Msaidie1,6, Axel Ducourneau1,2,5,6, Gilles Boetsch1, Guy Longepied2, Kassim Papa1, Claude Allibert3, Ali Ahmed Yahaya4, Jacques Chiaroni1 and Michael J Mitchell2

  1. 1UMR 6578, Anthropologie Bio-culturelle, CNRS-EFS-Université de la Méditerranée, Faculté de médecine Hôpital Nord, Marseille, France
  2. 2Inserm UMR S910, Génétique Médicale et Génomique Fonctionnelle, Inserm-Université de la Méditerranée, Marseille, France
  3. 3Institut national des Langues et Civilisations orientales, Paris, France
  4. 4Laboratoire de Biologie de l’Hôpital El-Maarouf, Moroni, Comoros
  5. 5Leverhulme Centre for Human Evolutionary Studies, University of Cambridge, Cambridge, UK

Correspondence: Dr MJ Mitchell, Inserm UMR_S 910, Faculté de médecine, 27 bd Jean Moulin, Marseille, cedex 05 13385, France. Tel: +33 4 01257154; Fax: +33 4 91804319; E-mail: michael.mitchell@univmed.fr; J Chiaroni, EFS Alpes Méditerranée, UMR 6578, Université de la Méditerranée, 149 Boulevard Baille, Marseille 13005, France. E-mail: jacques.chiaroni@efs.sante.fr

6These authors contributed equally to this work.

Received 10 March 2009; Revised 23 June 2010; Accepted 29 June 2010; Published online 11 August 2010.

Top

Abstract

The Comoros Islands are situated off the coast of East Africa, at the northern entrance of the channel of Mozambique. Contemporary Comoros society displays linguistic, cultural and religious features that are indicators of interactions between African, Middle Eastern and Southeast Asian (SEA) populations. Influences came from the north, brought by the Arab and Persian traders whose maritime routes extended to Madagascar by 700–900 AD. Influences also came from the Far East, with the long-distance colonisation by Austronesian seafarers that reached Madagascar 1500 years ago. Indeed, strong genetic evidence for a SEA, but not a Middle Eastern, contribution has been found on Madagascar, but no genetic trace of either migration has been shown to exist in mainland Africa. Studying genetic diversity on the Comoros Islands could therefore provide new insights into human movement in the Indian Ocean. Here, we describe Y chromosomal and mitochondrial genetic variation in 577 Comorian islanders. We have defined 28 Y chromosomal and 9 mitochondrial lineages. We show the Comoros population to be a genetic mosaic, the result of tripartite gene flow from Africa, the Middle East and Southeast Asia. A distinctive profile of African haplogroups, shared with Madagascar, may be characteristic of coastal sub-Saharan East Africa. Finally, the absence of any maternal contribution from Western Eurasia strongly implicates male-dominated trade and religion as the drivers of gene flow from the North. The Comoros provides a first view of the genetic makeup of coastal East Africa.

Keywords:

Y chromosome; mitochondrion; Indian Ocean; East Africa; Comoros