Mode de vie et diversité génétique dans les populations humaines d'Asie Centrale

Abstract : This thesis aims at asking to which extent lifestyle shapes the human genetic diversity. In order to tackle this issue, we have chosen to study different ethnic groups in Central Asia, which have contrasted social organization and modes of subsistence. We have first compared the a priori neutral genetic diversity of patrilineal and cognatic societies (the individuals are defined through their paternal filiation or equally through both sexes, respectively). This study, based on the autosomes and the X chromosome allowed us to show that men have a reduced effective population size and migration rate as compared to that of women in patrilineal but not in cognatic societies. Therefore, this contrasted sex-specific genetic structure seems to be the direct consequence of the patrilineal social organization. Then, we have tested if herders and farmers have undergone distinct selective pressures linked to diet. For the lactase gene, (digestion of lactose into adulthood) and for the AGXT gene (facilitating meat digestion), we have not found differences in genetic diversity between populations. However, we could show that herders (represented by Kyrgyz) have nearly twice more insulin resistance, a phenotype proposed as an adaptation to little amounts of carbohydrates in the diet, than farmers (represetned by Tajik). Furthermore, we have found some signatures on local adaptation on some genes associated with insulin resistance. Hence, herders and farmers in Central Asia seem to have adapted to different diet. This thesis therefore supports the influence of cultural factors on the evolution of genetic diversity in human populations.
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Contributor : Segurel Laure <>
Submitted on : Thursday, December 16, 2010 - 5:33:47 PM
Last modification on : Tuesday, May 7, 2019 - 3:30:03 PM
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Laure Ségurel. Mode de vie et diversité génétique dans les populations humaines d'Asie Centrale. Ecologie, Environnement. Université Pierre et Marie Curie - Paris VI, 2010. Français. ⟨tel-00547600⟩

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