AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 136:100–107 (2008) Admixture and Sexual Bias in the Population Settlement of La Re´ union Island (Indian Ocean) Gemma Berniell-Lee,1 Ste´ phanie Plaza,2 Elena Bosch,1,3 Francesc Calafell,1,3 Eric Jourdan,4 Maya Ce´ sari,5 Ge´ rard Lefranc,6 and David Comas1,3* 1Unitat de Biologia Evolutiva, Departament de Cie`ncies Experimentals i de la Salut, Universitat Pompeu Fabra, 08003 Barcelona, Spain 2Servei de Geno`mica., Departament de Cie`ncies Experimentals i de la Salut, Universitat Pompeu Fabra, 08003 Barcelona, Spain 3CIBER Epidemiologı´a y Salud Pu´ blica (CIBERESP), Spain 4De´partement d’He´matologie Clinique et Oncologie Me´dicale, Groupe Hospitalo-Universitaire Caremeau, 30029 Nıˆmes, France 5UFR de Biologie, Universite´ de La Re´union, 97715 Saint-Denis, Messag. Cedex 9 – Re´union, France DOM 6Institut de Ge´ne´tique Humaine, UPR CNRS 1142, et Universite´ Montpellier II, 34095 Montpellier Cedex 5, France KEY WORDS mixed ancestry; asymmetrical gene flow; mtDNA; Y chromosome; founder effects ABSTRACT La Re´union, one of the three Mascarene further 18 STRs and 35 SNPs on the Y chromosome in islands located in the Indian Ocean, remained devoid of 26 of these samples. Our results show that there was a inhabitants until it was first colonized by the French in strong sexual bias (asymmetrical gene flow) in the peo- the middle of the 17th century. The continuous flow of pling of La Re´union, where admixture events were foreign-born slaves and immigrant workers from Africa, mainly between male settlers and females from the India, Southeast Asia, and China to work on coffee and incoming slave groups. Most of the Y-chromosome gene sugar cane plantations led to the island becoming a pool is of European/Middle Eastern ancestry (85%), melting pot of people of multiple ethnic origins. To es- whereas the mtDNA gene pool is mainly of Indian tablish the impact of the different incoming ethnic and East Asian ancestry (70%). The absence of genetic groups on the present Reunionese gene pool, we have diversity within these two major components of sequenced both hypervariable regions I and II of the the mtDNA gene pool suggests these populations may mitochondrial DNA molecule, the 9 bp COII/tRNALys have witnessed strong founder effects during the coloni- deletion, and four SNPs located in the coding region in zation process. Am J Phys Anthropol 136:100–107, a total of 41 samples of the general population, and a 2008. VC 2008 Wiley-Liss, Inc. The Mascarene islands are a group of islands located Southeast Asia (especially Malays and Anamites), and in the Indian Ocean 690 km East of Madagascar, off the China (Ostheimer 1975; Lavaux 1988). The continuous southeastern coast of Africa (Fig. 1). Also known as the flow of foreign-born slaves and immigrant contracted Mascarenhas archipelago, named after its discoverer, the labourers from diverse locations created a highly multi- Portuguese navigator Pedro Mascarenhas, it is composed cultural and multilingual population structure that with of three islands; Mauritius, Re´union and Rodrigues. time has led to the island becoming a mosaic of people of Rodrigues is a dependency of Mauritius, and La Re´union multiple ethnic origins. Such is the case, that La Re´- is one of the six French overseas departments or De´part- union has currently a largely admixed population of over ments d’Outre-Mer (DOM). 780,000 inhabitants (Institut National de la Statistique The Mascarenhas archipelago remained desert islands et des E´ tudes E´ conomiques, INSEE, http://www.insee.fr) for a long time, and although it was apparently already belonging to six main ethnic groups: the Malbars (or known to Arab merchants who sailed the Indian Ocean, it was not discovered until the 16th century by the Por- tuguese. From then onwards, the islands remained unin- habited until they were colonized by the French in the Grant sponsor: Direccio´n General de Investigacio´n, Ministerio de middle of the 17th century. With the arrival of the first Educacio´n y Ciencia, Spain; Grant number: CGL2007-61016; Grant ´ few French settlers to La Re´union came an influx of sponsor: Direccio General de Recerca, Generalitat de Catalunya; Grant number: 2005SGR/00608. African slaves (especially from East Africa and Madagas- car) (Ostheimer, 1975; Lavaux, 1988) to work on coffee *Correspondence to: David Comas, Unitat de Biologia Evolutiva, and sugar plantations. The import of slaves continued Universitat Pompeu Fabra, Doctor Aiguader 88, 08003 Barcelona, well into the middle of the 19th century, when slavery Spain. E-mail: [email protected] was finally abolished in 1848. It is thought that during this slave trade period more than 60,000 slaves were Received 4 July 2007; accepted 14 November 2007 imported into La Re´union (Ostheimer, 1975; Lavaux, 1988). To fill in the vacancies left by the slaves, the Eu- DOI 10.1002/ajpa.20783 ropean landowners then recruited thousands of inden- Published online 10 January 2008 in Wiley InterScience tured labourers mainly from India (especially Malabars), (www.interscience.wiley.com). VC 2008 WILEY-LISS, INC. UNIPARENTAL MARKERS IN LA RE´ UNION 101 MATERIALS AND METHODS Blood samples were obtained from 41 randomly selected and unrelated individuals. Given the largely admixed nature of the population of La Re´union, where nearly half of the population is considered me´tis (Ce´sari, 1999, doctoral thesis), defining the precise ethnic origin of an individual is sometimes problematic, most having several different ethnic groups in their genealogical line and identifying themselves with several groups, a phe- nomenon common in multiethnic societies (Yu-Sion, 2003). This is the case of the 41 samples used here, where the individuals themselves could not be precise about their exact ethnic origin. They did ensure, how- ever, that they were Re´unionese as far back as three generations (at least), with their grandparents (both maternal and paternal) and parents having been born in La Re´union. We have considered these samples to be representative of the general population of la Re´union. Fig. 1. Map of La Re´union island. DNA was extracted using standard phenol-chloroform methods. Malabars), descendents of Indian workers imported to Mitochondrial and Y-chromosome typing La Re´union after the abolition of slavery; the Zarabes For the mtDNA, both hypervariable regions, the 9-bp (derived from the French les Arabes, the Arabs), Lys descendents of Muslim Indians imported at the end of tandem repeat (CCCCCTCTA) of the COII/tRNA inter- the 19th century; the Chinois, descendents of the Chi- genic region, and positions 10,400, 10,873, 12,308, and nese; the Zoreilles (derived from the French words les 12,705 in the coding region of the molecule (according oreilles, the ears) descendents of the European settlers; to Anderson et al., 1981) were typed as previously the Caffres, the descendents of the African slaves, and described (Comas et al., 2004). Sequences from positions the Creoles, the rest of the admixed population. 16,024 to 16,391 and from 63 to 322 (according to To our knowledge, there is no information on the (Anderson et al., 1981) were used in the present analy- genetic diversity present in the population of La Re´- sis. Previously published mtDNA data for several Asian union. A few genetic studies have focused on Madagas- and African populations were used for comparison pur- car (Soodyall et al., 1995; Hewitt et al., 1996; Hurles et poses (Mountain et al., 1995; Horai et al., 1996; Kivisild al., 2005), the Mascarenhas closest neighbouring island, et al., 1999; Lum and Cann, 2000; Richards et al., 2000; which was originally settled from Indonesia according to Bamshad et al., 2001; Fucharoen et al., 2001; Kivisild linguistic and archaeological evidence (Dahl, 1951; Ve´rin et al., 2002; Salas et al., 2002; Yao and Zhang, 2002; Hurles and Wright, 1999). Using data on the beta-globin gene, et al., 2005). HVR I sequences classified as European Hewitt et al. (1996) showed that Malagasy individuals according to the well-established mtDNA phylogeogra- present a strong Central and East African component, phy (Richards et al., 2000), were compared with a Euro- specifically a Bantu component, together with a smaller pean database of sequences from 14,382 individuals col- Asian/Oceanic and European component. Using mito- lected from 68 published articles (Calafell, unpublished chondrial DNA, Soodyall et al. (1995) suggested that data). For the Y chromosome analysis, 35 biallelic maternal lineages from Madagascar had a mixed markers and 18 microsatellite markers were typed. The African/Polynesian origin. This observation was later re- binary markers defining major Y-chromosome hap- inforced and elaborated further by Hurles et al. (2005), logroups were genotyped as previously described by who using both mitochondrial and Y chromosome data, (Berniell-Lee et al., 2007). The STRs were amplified in demonstrated an approximately equal African and Indo- the form of three previously described multiplex reac- nesian contribution to both paternal and maternal Mala- tions: MSI multiplex DYS 19, DYS 388, DYS 390, DYS gasy lineages. 391, DYS 392, DYS 393 (Bosch et al., 2002); CTS multi- MtDNA and the Y chromosome are haploid (or unipar- plex DYS 434, DYS 435, DYS 436, DYS 437, DYS 438, ental) markers, inherited from the mother and the fa- DYS 439 (Ayub et al., 2000) and EBF multiplex DYS 389 ther, respectively. Both these types of DNA have a well- I, DYS 389 II, DYS 462, DYS 460, DYS 461, DYS 385 established phylogeography (geographic distribution of (Bosch et al., 2002). PCR cycling conditions for multiplex lineages) which makes them ideal tools for the tracing of MSI were modified from Bosch et al. (2002) as follows: 8 8 8 both female and male ancestry.