一種用于區(qū)分西非人、非洲裔美國(guó)人和歐洲裔美國(guó)人的基因型分析可能幫助科學(xué)家理解各個(gè)人群的世系,，并且通過(guò)遺傳傾向研究健康與醫(yī)藥,。
Sarah Tishkoff及其同事使用來(lái)自西非人、非洲裔美國(guó)人和歐洲裔美國(guó)人的高密度基因型數(shù)據(jù)從而研究了它們是否能夠可靠地區(qū)分各個(gè)西非人群并確定非洲裔美國(guó)人的具體非洲祖先世系,。這組作者發(fā)現(xiàn),，盡管一些西非人群幾乎無(wú)法區(qū)分，被語(yǔ)言和地理界限分隔的一些群體存在可以辨識(shí)的遺傳差異,。這項(xiàng)研究還凸顯了非洲裔美國(guó)人祖先世系如同豐富的馬賽克一般,，此前還沒(méi)有被很好地記錄下來(lái)。在該研究的365名非洲裔美國(guó)人中,，個(gè)體的西非祖先世系在99%到小于1%之間,。非洲裔美國(guó)人的西非成分最類似于非班圖、說(shuō)尼日爾一科爾多凡語(yǔ)的人群的遺傳譜,，這符合跨大西洋奴隸貿(mào)易的歷史記載,。這組科學(xué)家提出，他們的技術(shù)——這種技術(shù)經(jīng)過(guò)了修改從而增加了遺傳標(biāo)記的密度——最終可能更準(zhǔn)確地弄清非洲裔美國(guó)人的祖先世系,。（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS December 14, 2009, doi: 10.1073/pnas.0909559107
Genome-wide patterns of population structure and admixture in West Africans and African Americans
Katarzyna Bryca, Adam Autona, Matthew R. Nelsonb, Jorge R. Oksenbergc, Stephen L. Hauserc, Scott Williamsd, Alain Fromente, Jean-Marie Bodof, Charles Wambebeg, Sarah A. Tishkoffh,1,2 and Carlos D. Bustamantea,1,3
aDepartment of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY 14853
b GlaxoSmithKline, Research Triangle Park, NC 27709
cDepartment of Neurology, University of California, San Francisco, CA 94143
dDepartment of Molecular Physiology and Biophysics, Center for Human Genetics Research, Vanderbilt University, Nashville, TN 37232
eUnité Mixte de Recherche 208, Institut de recherche pour le développement (IRD)-Muséum national d’Histoire naturelle (MNHN), Musée de l’Homme, 75116 Paris, France
f Ministére de la Recherche Scientifique et de l’Innovation, BP 1457, Yaoundé, Cameroon
g International Biomedical Research in Africa, Abuja, Nigeria
hDepartments of Genetics and Biology, University of Pennsylvania, Philadelphia, PA 19104
Quantifying patterns of population structure in Africans and African Americans illuminates the history of human populations and is critical for undertaking medical genomic studies on a global scale. To obtain a fine-scale genome-wide perspective of ancestry, we analyze Affymetrix GeneChip 500K genotype data from African Americans (n = 365) and individuals with ancestry from West Africa (n = 203 from 12 populations) and Europe (n = 400 from 42 countries). We find that population structure within the West African sample reflects primarily language and secondarily geographical distance, echoing the Bantu expansion. Among African Americans, analysis of genomic admixture by a principal component-based approach indicates that the median proportion of European ancestry is 18.5% (25th–75th percentiles: 11.6–27.7%), with very large variation among individuals. In the African-American sample as a whole, few autosomal regions showed exceptionally high or low mean African ancestry, but the X chromosome showed elevated levels of African ancestry, consistent with a sex-biased pattern of gene flow with an excess of European male and African female ancestry. We also find that genomic profiles of individual African Americans afford personalized ancestry reconstructions differentiating ancient vs. recent European and African ancestry. Finally, patterns of genetic similarity among inferred African segments of African-American genomes and genomes of contemporary African populations included in this study suggest African ancestry is most similar to non-Bantu Niger-Kordofanian-speaking populations, consistent with historical documents of the African Diaspora and trans-Atlantic slave trade.
