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Proc Natl Acad Sci U S A. 2015 Jul 14;112(28):8696-701. doi: 10.1073/pnas.1504447112. Epub 2015 Jun 29.

Origin and dynamics of admixture in Brazilians and its effect on the pattern of deleterious mutations.

Author information

1
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Minas Gerais, Brazil;
2
Instituto do Coração, Universidade de São Paulo, 05403-900, São Paulo, Sao Paulo, Brazil;
3
Programa de Pós-Graduação em Epidemiologia, Universidade Federal de Pelotas, 464, 96001-970 Pelotas, Rio Grande do Sul, Brazil;
4
Departamento de Estatística, Instituto de Matemática, Universidade Federal da Bahia, 40170-110, Salvador, Bahia, Brazil;
5
Departamento de Ciências da Biointeração, Instituto de Ciências da Saúde, Universidade Federal da Bahia, 40110-100, Salvador, Bahia, Brazil;
6
Instituto de Saúde Coletiva, Universidade Federal da Bahia, 40110-040, Salvador, Bahia, Brazil;
7
Department of Genetics, University of Leicester, LE1 7RH, Leicester, United Kingdom;
8
Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110; Department of Medicine, University of California, San Diego, CA 92093;
9
Biomedical Research Unit, Asociación Benéfica Proyectos en Informática, Salud, Medicina y Agricultura (AB PRISMA), 170070, Lima, Peru;
10
Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina, Brazil;
11
Departamento de Estatística, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Minas Gerais, Brazil;
12
Dipartimento di Scienze della Vita e Biotecnologie, Università di Ferrara, 44121 Ferrara, Italy;
13
Bloomberg School of Public Health, International Health, Johns Hopkins University, Baltimore, MD 21205; Laboratorio de Investigación de Enfermedades Infecciosas, Universidade Peruana Cayetano Heredia, 15102, Lima, Peru;
14
Department of Psychiatry and Neuroscience Section, Center for Addiction and Mental Health, University of Toronto, Toronto, ON, Canada M5T 1R8;
15
Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, 6020 Innsbruck, Austria;
16
Cancer Genomics Research Laboratory, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 20850;
17
Department of Infectious Disease Epidemiology, Faculty of Epidemiology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom;
18
Instituto de Pesquisa Rene Rachou, Fundação Oswaldo Cruz, 30190-002, Belo Horizonte, Minas Gerais, Brazil.
19
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Minas Gerais, Brazil; edutars@icb.ufmg.br.

Abstract

While South Americans are underrepresented in human genomic diversity studies, Brazil has been a classical model for population genetics studies on admixture. We present the results of the EPIGEN Brazil Initiative, the most comprehensive up-to-date genomic analysis of any Latin-American population. A population-based genome-wide analysis of 6,487 individuals was performed in the context of worldwide genomic diversity to elucidate how ancestry, kinship, and inbreeding interact in three populations with different histories from the Northeast (African ancestry: 50%), Southeast, and South (both with European ancestry >70%) of Brazil. We showed that ancestry-positive assortative mating permeated Brazilian history. We traced European ancestry in the Southeast/South to a wider European/Middle Eastern region with respect to the Northeast, where ancestry seems restricted to Iberia. By developing an approximate Bayesian computation framework, we infer more recent European immigration to the Southeast/South than to the Northeast. Also, the observed low Native-American ancestry (6-8%) was mostly introduced in different regions of Brazil soon after the European Conquest. We broadened our understanding of the African diaspora, the major destination of which was Brazil, by revealing that Brazilians display two within-Africa ancestry components: one associated with non-Bantu/western Africans (more evident in the Northeast and African Americans) and one associated with Bantu/eastern Africans (more present in the Southeast/South). Furthermore, the whole-genome analysis of 30 individuals (42-fold deep coverage) shows that continental admixture rather than local post-Columbian history is the main and complex determinant of the individual amount of deleterious genotypes.

KEYWORDS:

Bambuí Cohort Study of Ageing; Latin America; Pelotas Birth Cohort Study; Salvador SCAALA; population genetics

PMID:
26124090
PMCID:
PMC4507185
DOI:
10.1073/pnas.1504447112
[Indexed for MEDLINE]
Free PMC Article

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