staff

André Langaney

Emeritus Professor in Anthropology & Immunogenetics

  • T: +41 22 379 63 24
  • office 4-415 (Sciences II)
  • Genetic evidence for complexity in ethnic differentiation and history in East Africa. Ann. Hum. Genet. 2009 Nov;73(Pt 6):582-600. AHG541. 10.1111/j.1469-1809.2009.00541.x.

    abstract

    The Afro-Asiatic and Nilo-Saharan language families come into contact in Western Ethiopia. Ethnic diversity is particularly high in the South, where the Nilo-Saharan Nyangatom and the Afro-Asiatic Daasanach dwell. Despite their linguistic differentiation, both populations rely on a similar agripastoralist mode of subsistence. Analysis of mitochondrial DNA extracted from Nyangatom and Daasanach archival sera revealed high levels of diversity, with most sequences belonging to the L haplogroups, the basal branches of the mitochondrial phylogeny. However, in sharp contrast with other Ethiopian populations, only 5% of the Nyangatom and Daasanach sequences belong to haplogroups M and N. The Nyangatom and Daasanach were found to be significantly differentiated, while each of them displays close affinities with some Tanzanian populations. The strong genetic structure found over East Africa was neither associated with geography nor with language, a result confirmed by the analysis of 6711 HVS-I sequences of 136 populations mainly from Africa. Processes of migration, language shift and group absorption are documented by linguists and ethnographers for the Nyangatom and Daasanach, thus pointing to the probably transient and plastic nature of these ethnic groups. These processes, associated with periods of isolation, could explain the high diversity and strong genetic structure found in East Africa.

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  • Worldwide distribution of NAT2 diversity: implications for NAT2 evolutionary history. BMC Genet. 2008 ;9():21. 1471-2156-9-21. 10.1186/1471-2156-9-21. PMC2292740.

    abstract

    The N-acetyltransferase 2 (NAT2) gene plays a crucial role in the metabolism of many drugs and xenobiotics. As it represents a likely target of population-specific selection pressures, we fully sequenced the NAT2 coding region in 97 Mandenka individuals from Senegal, and compared these sequences to extant data on other African populations. The Mandenka data were further included in a worldwide dataset composed of 41 published population samples (6,727 individuals) from four continental regions that were adequately genotyped for all common NAT2 variants so as to provide further insights into the worldwide haplotype diversity and population structure at NAT2.

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  • Haplotype tagging efficiency and tagSNP sets portability in worldwide populations in NAT2 gene (Marquage d'haplotypes du gène NAT2 : efficacité dans différentes régions du monde) Bull. et Mém. Soc. d'Anthropologie de Paris 19(3-4):233-241 (2007)

    abstract

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  • Génétique, linguistique et histoire des peuplements humains Langages 146:80-90 (2002)

    abstract

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  • Molecular analysis of the beta-globin gene cluster in the Niokholo Mandenka population reveals a recent origin of the beta(S) Senegal mutation. Am. J. Hum. Genet. 2002 Jan;70(1):207-23. S0002-9297(07)61294-4. 10.1086/338304. PMC384889.

    abstract

    A large and ethnically well-defined Mandenka sample from eastern Senegal was analyzed for the polymorphism of the beta-globin gene cluster on chromosome 11. Five RFLP sites of the 5' region were investigated in 193 individuals revealing the presence of 10 different haplotypes. The frequency of the sickle-cell anemia causing mutation (beta(S)) in the Mandenka estimated from this sample is 11.7%. This mutation was found strictly associated with the single Senegal haplotype. Approximately 600 bp of the upstream region of the beta-globin gene were sequenced for a subset of 94 chromosomes, showing the presence of four transversions, five transitions, and a composite microsatellite polymorphism. The sequence of 22 beta(S) chromosomes was also identical to the previously defined Senegal haplotype, suggesting that this mutation is very recent. Monte Carlo simulations (allowing for a specific balancing selection model, a logistic growth of the population, and variable initial frequencies of the Senegal haplotype) were used to estimate the age of the beta(S) mutation. Resulting maximum-likelihood estimates are 45-70 generations (1,350-2,100 years) for very different demographic scenarios. Smallest confidence intervals (25-690 generations) are obtained under the hypothesis that the Mandenka population is large (N(e) >5,000) and stationary or that it has undergone a rapid demographic expansion to a current size of >5,000 reproducing individuals, which is quite likely in view of the great diversity found on beta(A) chromosomes.

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  • La langue paternelle Sciences et Avenir, Hors-série (Quelle langue parlait-on il y a 100 000 ans?: la langue d'Homo erectus) 125:42-49 (2000-2001)

    abstract

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  • The molecular diversity of the Niokholo Mandenkalu from Eastern Senegal: An insight into West Africa genetic history In: Boyce AJ and Mascie-Taylor CGN, eds. Molecular Biology and Human Diversity. Cambridge: Cambridge University Press, p.141-155 (1996)

    abstract

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  • L'Homme descend du sexe La Recherche 20:994-1007 (1989)

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