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Genome-wide studies of African populations have the potential to reveal powerful insights into the evolution of our species, as these diverse populations have been exposed to intense selective pressures imposed by infectious diseases, diet, and environmental factors. Within Africa, the Sahel Belt extensively overlaps the geographical center of several endemic infections such as malaria, trypanosomiasis, meningitis, and hemorrhagic fevers. We screened 2.5 million single nucleotide polymorphisms in 161 individuals from 13 Sahelian populations, which together with published data cover Western, Central, and Eastern Sahel, and include both nomadic and sedentary groups. We confirmed the role of this Belt as a main corridor for human migrations across the continent. Strong admixture was observed in both Central and Eastern Sahelian populations, with North Africans and Near Eastern/Arabians, respectively, but it was inexistent in Western Sahelian populations. Genome-wide local ancestry inference in admixed Sahelian populations revealed several candidate regions that were significantly enriched for non-autochthonous haplotypes, and many showed to be under positive selection. The DARC gene region in Arabs and Nubians was enriched for African ancestry, whereas the RAB3GAP1/LCT/MCM6 region in Oromo, the TAS2R gene family in Fulani, and the ALMS1/NAT8 in Turkana and Samburu were enriched for non-African ancestry. Signals of positive selection varied in terms of geographic amplitude. Some genomic regions were selected across the Belt, the most striking example being the malaria-related DARC gene. Others were Western-specific (oxytocin, calcium, and heart pathways), Eastern-specific (lipid pathways), or even population-restricted (TAS2R genes in Fulani, which may reflect sexual selection). ; People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013/ under REA grant agreement no. 290344 (EUROTAST). This project was also supported by the Grant Agency of the Czech Republic ...

WOS: 000398562100001 ; PubMed ID: 28387361 ; Human mitochondrial DNA haplogroup U is among the initial maternal founders in Southwest Asia and Europe and one that best indicates matrilineal genetic continuity between late Pleistocene huntergatherer groups and present-day populations of Europe. While most haplogroup U subclades are older than 30 thousand years, the comparatively recent coalescence time of the extant variation of haplogroup U7 (-16-19 thousand years ago) suggests that its current distribution is the consequence of more recent dispersal events, despite its wide geographical range across Europe, the Near East and South Asia. Here we report 267 new U7 mitogenomes that -analysed alongside 100 published ones -enable us to discern at least two distinct temporal phases of dispersal, both of which most likely emanated from the Near East. The earlier one began prior to the Holocene (-11.5 thousand years ago) towards South Asia, while the later dispersal took place more recently towards Mediterranean Europe during the Neolithic (-8 thousand years ago). These findings imply that the carriers of haplogroup U7 spread to South Asia and Europe before the suggested Bronze Age expansion of Indo-European languages from the Pontic-Caspian Steppe region. ; Estonian Institutional Research grant [IUT24-1]; ERC Starting Investigator grant [FP7-261213]; EU European Regional Development Fund through the Centre of Excellence in Genomics to Estonian Biocentre; Estonian Research Council grant [PUT1339, PUT1217, PUT766]; University of Pavia strategic theme "Towards a governance model for international migration: an interdisciplinary and diachronic perspective" (MIGRAT-IN-G); Italian Ministry of Education, University and Research: Futuro in Ricerca [RBFR126B8I]; Progetti Ricerca Interesse Nazionale; Council of Scientific and Industrial Research, Government of India (GENESIS) [BSC0121, BSC 0118]; National geographic Society through Genographic Project Research Grant [6-13]; European Social Fund's Doctoral Studies and Internationalisation Programme DoRa; Leverhulme Trust's Doctoral Scholarship programme; University of Huddersfield's University Research Fund and Research Excellent Staff Scheme; FCT Investigator Programme [IF/01641/2013] ; We thank all the DNA donors who participated in this study. This study was supported by Estonian Institutional Research grant IUT24-1 (to H.S., E.M., M.R., M.M., T.K., and R.V.); ERC Starting Investigator grant (FP7-261213) (to T.K.); EU European Regional Development Fund through the Centre of Excellence in Genomics to Estonian Biocentre; Estonian Research Council grant PUT1339 (to A.K.), PUT1217 (to Kr.T.) and PUT766 (to G.C.); the University of Pavia strategic theme "Towards a governance model for international migration: an interdisciplinary and diachronic perspective" (MIGRAT-IN-G); the Italian Ministry of Education, University and Research: Futuro in Ricerca 2012 (RBFR126B8I) (to A.A. and A.O.) and Progetti Ricerca Interesse Nazionale 2012 (to A.A., O.S., and A.T.); the Council of Scientific and Industrial Research, Government of India (GENESIS: BSC0121) and (BSC 0118) (to Ku.T.); S.S. and E.R. acknowledge the support of National geographic Society through Genographic Project Research Grant (6-13). R.T. and A.K.P. were supported by the European Social Fund's Doctoral Studies and Internationalisation Programme DoRa. M.B.R. received support from the Leverhulme Trust's Doctoral Scholarship programme, and F.G. from the University of Huddersfield's University Research Fund and Research Excellent Staff Scheme. P.S. was supported by the FCT Investigator Programme (IF/01641/2013).