Chad Genetic Diversity Reveals an African History Marked by Multiple Holocene Eurasian Migrations.
Chad Genetic Diversity Reveals an African History Marked by Multiple Holocene Eurasian Migrations.
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DOI：
10.1016/j.ajhg.2016.10.012
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发表时间：
2016-12-01
影响因子：
9.8
通讯作者：
Tyler-Smith C
中科院分区：
文献类型：
--
作者：
Haber M;Mezzavilla M;Bergström A;Prado-Martinez J;Hallast P;Saif-Ali R;Al-Habori M;Dedoussis G;Zeggini E;Blue-Smith J;Wells RS;Xue Y;Zalloua PA;Tyler-Smith C
了解非洲的人类遗传多样性对于解释所有人类的进化非常重要，但非洲的广大地区，如乍得，仍然对遗传学研究不足。在这里，我们使用来自乍得，近东和南欧的480个样本的基因型数据，以及其中19个样本的全基因组测序，以表明今天许多人群的基因组来自古老的非洲-欧亚混合物。我们在乍得南部讲未分类的孤立的拉尔语的人中发现了早期欧亚回流到非洲的证据，并从联系不平衡衰减估计这发生在4，750 - 7，200年前。它给非洲带来了一个Y染色体谱系（R1 b-V88），它的近亲在今天的欧亚大陆广泛分布;我们根据序列数据估计，乍得R1 b-V88 Y染色体在5，700 - 7，300年前合并。因此，这种迁移可能起源于非洲潮湿时期的近东农民。我们还发现，先前记录的欧亚回流到非洲，发生在13000年前，被认为主要限于东非，对乍得北方的人口产生了更向西的影响，如图布人，他们今天有20%-30%的欧亚血统。我们观察到混合非洲人的杂合性下降，并发现欧亚混合物可以偏见推断其合并的历史和混淆适应和古老的基因渗入的遗传信号。
Understanding human genetic diversity in Africa is important for interpreting the evolution of all humans, yet vast regions in Africa, such as Chad, remain genetically poorly investigated. Here, we use genotype data from 480 samples from Chad, the Near East, and southern Europe, as well as whole-genome sequencing from 19 of them, to show that many populations today derive their genomes from ancient African-Eurasian admixtures. We found evidence of early Eurasian backflow to Africa in people speaking the unclassified isolate Laal language in southern Chad and estimate from linkage-disequilibrium decay that this occurred 4,750–7,200 years ago. It brought to Africa a Y chromosome lineage (R1b-V88) whose closest relatives are widespread in present-day Eurasia; we estimate from sequence data that the Chad R1b-V88 Y chromosomes coalesced 5,700–7,300 years ago. This migration could thus have originated among Near Eastern farmers during the African Humid Period. We also found that the previously documented Eurasian backflow into Africa, which occurred ∼3,000 years ago and was thought to be mostly limited to East Africa, had a more westward impact affecting populations in northern Chad, such as the Toubou, who have 20%–30% Eurasian ancestry today. We observed a decline in heterozygosity in admixed Africans and found that the Eurasian admixture can bias inferences on their coalescent history and confound genetic signals from adaptation and archaic introgression.
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影响因子：
64.8
作者：
Gurdasani, Deepti;Carstensen, Tommy;Tekola-Ayele, Fasil;Pagani, Luca;Tachmazidou, Ioanna;Hatzikotoulas, Konstantinos;Karthikeyan, Savita;Iles, Louise;Pollard, Martin O.;Choudhury, Ananyo;Ritchie, GrahamR. S.;Xue, Yali;Asimit, Jennifer;Nsubuga, Rebecca N.;Young, Elizabeth H.;Pomilla, Cristina;Kivinen, Katja;Rockett, Kirk;Kamali, Anatoli;Doumatey, Ayo P.;Asiki, Gershim;Seeley, Janet;Sisay-Joof, Fatoumatta;Jallow, Muminatou;Tollman, Stephen;Mekonnen, Ephrem;Ekong, Rosemary;Oljira, Tamiru;Bradman, Neil;Bojang, Kalifa;Ramsay, Michele;Adeyemo, Adebowale;Bekele, Endashaw;Motala, Ayesha;Norris, Shane A.;Pirie, Fraser;Kaleebu, Pontiano;Kwiatkowski, Dominic;Tyler-Smith, Chris;Rotimi, Charles;Zeggini, Eleftheria;Sandhu, Manjinder S.
通讯作者：
Sandhu, Manjinder S.
影响因子：
3.4
作者：
Cerný V;Fernandes V;Costa MD;Hájek M;Mulligan CJ;Pereira L
通讯作者：
Pereira L
影响因子：
56.9
作者：
Kroepelin, S.;Verschuren, D.;Engstrom, D. R.
通讯作者：
Engstrom, D. R.
影响因子：
64.8
作者：
Li, Heng;Durbin, Richard
通讯作者：
Durbin, Richard
影响因子：
9.8
作者：
Balaresque P;Bowden GR;Adams SM;Leung HY;King TE;Rosser ZH;Goodwin J;Moisan JP;Richard C;Millward A;Demaine AG;Barbujani G;Previderè C;Wilson IJ;Tyler-Smith C;Jobling MA
通讯作者：
Jobling MA