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[QUOTE]Originally posted by DD'eDeN: [QB] Madagascar - 1st Malays, then Bantus arrived Madagascar settlement pattern: http://www.pnas.org/content/early/2017/07/11/1704906114.abstract The origins of the Malagasy raise questions about ancient connections between continents; moreover, because ancestors are fundamental to Malagasy society, Malagasy origins is also a heated topic around the country, with numerous proposed hypotheses. This study provides a comprehensive view of genomic diversity (including maternal lineages, paternal lineages, and genome-wide data) based on a sampling of 257 villages across Madagascar. The observed spatial patterns lead to a scenario of a recent and sex-biased admixture between Bantu and Austronesian ancestors across the island. Moreover, we find geographical influences creating subtle signals of genetic structure that are independent of the Bantu/Austronesian admixture, suggesting that recent history has a role in the genomic diversity of the Malagasy. Madagascar had a hunting & gathering tribe distinct from the Bantu and Malayan agriculturalists, this study has found the Mikea tribe is a mixture of both. http://www.pnas.org/content/111/3/936.long The Mikea are the last known Malagasy population reported to be still practicing a hunter-gatherer lifestyle. Earlier writers thought the Mikea were descended from ancient forager groups who have maintained their way of life up to the present. However, our analyses show that the Mikea are not a remnant population and, to the contrary, derived from a recent admixture of two agriculturalist populations: the Bantu (from Africa) and the Austronesian (from east-Asia). Thus, it is probable that the Mikea have adopted their hunter-gatherer way of life through a recent cultural reversion Vivax malaria suscepatability in Africans vs non-Africans per Duffy gene http://www.pnas.org/content/107/13/5967.long Malaria therapy, experimental, and epidemiological studies have shown that erythrocyte Duffy blood group-negative people, largely of African ancestry, are resistant to erythrocyte Plasmodium vivax infection. These findings established a paradigm that the Duffy antigen is required for P. vivax erythrocyte invasion. P. vivax is endemic in Madagascar, where admixture of Duffy-negative and Duffy-positive populations of diverse ethnic backgrounds has occurred over 2 millennia. There, we investigated susceptibility to P. vivax blood-stage infection and disease in association with Duffy blood group polymorphism. Duffy blood group genotyping identified 72% Duffy-negative individuals (FY*BES/*BES) in community surveys conducted at eight sentinel sites. Flow cytometry and adsorption–elution results confirmed the absence of Duffy antigen expression on Duffy-negative erythrocytes. P. vivax PCR positivity was observed in 8.8% (42/476) of asymptomatic Duffy-negative people. Clinical vivax malaria was identified in Duffy-negative subjects with nine P. vivax monoinfections and eight mixed Plasmodium species infections that included P. vivax (4.9 and 4.4% of 183 participants, respectively). Microscopy examination of blood smears confirmed blood-stage development of P. vivax, including gametocytes. Genotyping of polymorphic surface and microsatellite markers suggested that multiple P. vivax strains were infecting Duffy-negative people. In Madagascar, P. vivax has broken through its dependence on the Duffy antigen for establishing human blood-stage infection and disease. Further studies are necessary to identify the parasite and host molecules that enable this Duffy-independent P. vivax invasion of human erythrocytes. During malaria fever therapy trials, performed to treat neurosyphilis (1920s to 1960s) and in experimental field trials, it was consistently demonstrated that Africans and African-Americans were highly resistant to Plasmodium vivax blood-stage malaria when challenged with human blood or mosquitoes infected with limited numbers of P. vivax strains (1–3). Following identification of the Duffy blood group (Fy; reviewed in Zimmerman, 2004) (4), population studies showed that individuals of African ancestry expressed neither Fya nor Fyb antigens and were classified as Duffy negative, Fy(a−b−) (5). Following on observations that vivax malaria was rare in Africa (6), Miller et al. performed definitive in vivo studies to show that Duffy-negative people resisted, whereas Duffy-positive people were susceptible, to experimental P. vivax blood-stage infection following exposure to infected mosquitoes (7). This seminal work, and related Plasmodium knowlesi in vitro studies (7–9), established the paradigm that malaria parasites invade erythrocytes through specific “receptor”-based interactions and that the Duffy blood group was the receptor for P. vivax. [/QB][/QUOTE]
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