By characterizing the geographic and functional spectrum of human genetic variation, the 1000 Genomes Project aims to build a resource to help to understand the genetic contribution to disease. Here we describe the genomes of 1,092 individuals from 14 populations, constructed using a combination of low-coverage whole-genome and exome sequencing. By developing methods to integrate information across several algorithms and diverse data sources, we provide a validated haplotype map of 38 million single nucleotide polymorphisms, 1.4 million short insertions and deletions, and more than 14,000 larger deletions. We show that individuals from different populations carry different profiles of rare and common variants, and that low-frequency variants show substantial geographic differentiation, which is further increased by the action of purifying selection. We show that evolutionary conservation and coding consequence are key determinants of the strength of purifying selection, that rare-variant load varies substantially across biological pathways, and that each individual contains hundreds of rare non-coding variants at conserved sites, such as motif-disrupting changes in transcription-factor-binding sites. This resource, which captures up to 98% of accessible single nucleotide polymorphisms at a frequency of 1% in related populations, enables analysis of common and low-frequency variants in individuals from diverse, including admixed, populations.

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An integrated map of genetic variation from 1,092 human genomes

Can part of Africa’s current underdevelopment be explained by its slave trades? To explore this question, I use data from shipping records and historical documents reporting slave ethnicities to construct estimates of the number of slaves exported from each country during Africa’s slave trades. I find a robust negative relationship between the number of slaves exported from a country and current economic performance. To better understand if the relationship is causal, I examine the historical evidence on selection into the slave trades, and use instrumental variables. Together the evidence suggests that the slave trades have had an adverse effect on economic development.

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The Long-term Effects of Africa's Slave Trades

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.

https://www.pnas.org/content/pnas/early/2009/12/10/0909559107.full.pdf

Genome-wide patterns of population structure and admixture in West Africans and African Americans

Les AA. explorent la definition et le sens meme de diaspora en tant que concept. Une grande part des debats actuels continue a suggerer que la diaspora est tout simplement une manifestation logique de la dispersion, qu'importe comment cette diaspora a ete creee ou depuis combien de temps elle existe. Les AA. tentent de demontrer que les relations qui lient la diaspora doivent s'articuler et ne sont pas inevitables, et que la diaspora est a la fois processus et condition. En tant que processus, elle est en permanence en cours de formation, et en tant que condition, elle se situe a l'interieur des hierarchies globales de race et de sexe (ou de genre). Cependant, tout comme la diaspora est faite, elle peut etre defaite et les chercheurs doivent ainsi examiner les moments de son demantelement. En effet, les efforts faits pour discerner les elements constitutifs de la ou des diasporas soulevent des questions importantes sur la facon dont l'Afrique est conceptualisee relativement a sa diaspora. Ces efforts mettent egalement en evidence la necessite d'examiner la superposition et l'intersection de diasporas issues de localisations historiques multiples.

Unfinished Migrations: Reflections on the African Diaspora and the Making of the Modern World

Preface Introduction 1 Encounters 2 Rice Origins and Indigenous Knowledge 3 Out of Africa: Rice Culture and African Continuities 4 This Was "Woman's Wuck" 5 African Rice and the Atlantic World 6 Legacies Notes References Index

Black Rice: The African Origins of Rice Cultivation in the Americas

Africans in colonial Louisiana : the development of Afro-Creole culture in the eighteenth century

The survival of African ethnic identities through four hundred years of the Atlantic slave trade Enslaved peoples were brought to the Americas from many places in Africa, but a large majority came from relatively few ethnic groups. Drawing on a wide range of materials in four languages as well as on her lifetime study of slave groups in the New World, Gwendolyn Midlo Hall explores the persistence of African ethnic identities among the enslaved over four hundred years of the Atlantic slave trade. Hall traces the linguistic, economic, and cultural ties shared by large numbers of enslaved Africans, showing that despite the fragmentation of the diaspora many ethnic groups retained enough cohesion to communicate and to transmit elements of their shared culture. Hall concludes that recognition of the survival and persistence of African ethnic identities can fundamentally reshape how people think about the emergence of identities among enslaved Africans and their descendants in the Americas, about the ways shared identity gave rise to resistance movements, and about the elements of common African ethnic traditions that influenced regional creole cultures throughout the Americas.

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Gwendolyn Midlo Hall

Papers

Africans in colonial Louisiana : the development of Afro-Creole culture in the eighteenth century

Slavery and African Ethnicities in the Americas: Restoring the Links

Africans in colonial Louisiana

Social Control in Slave Plantation Societies: A Comparison of St. Domingue and Cuba.

Social Control in Slave Plantation Societies: A Comparison of St. Domingue and Cuba