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Mester R, Hou K, Ding Y, Meeks G, Burch KS, Bhattacharya A, Henn BM, Pasaniuc B. Impact of cross-ancestry genetic architecture on GWASs in admixed populations. Am J Hum Genet 2023; 110:927-939. [PMID: 37224807 PMCID: PMC10257009 DOI: 10.1016/j.ajhg.2023.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/04/2023] [Accepted: 05/04/2023] [Indexed: 05/26/2023] Open
Abstract
Genome-wide association studies (GWASs) have identified thousands of variants for disease risk. These studies have predominantly been conducted in individuals of European ancestries, which raises questions about their transferability to individuals of other ancestries. Of particular interest are admixed populations, usually defined as populations with recent ancestry from two or more continental sources. Admixed genomes contain segments of distinct ancestries that vary in composition across individuals in the population, allowing for the same allele to induce risk for disease on different ancestral backgrounds. This mosaicism raises unique challenges for GWASs in admixed populations, such as the need to correctly adjust for population stratification. In this work we quantify the impact of differences in estimated allelic effect sizes for risk variants between ancestry backgrounds on association statistics. Specifically, while the possibility of estimated allelic effect-size heterogeneity by ancestry (HetLanc) can be modeled when performing a GWAS in admixed populations, the extent of HetLanc needed to overcome the penalty from an additional degree of freedom in the association statistic has not been thoroughly quantified. Using extensive simulations of admixed genotypes and phenotypes, we find that controlling for and conditioning effect sizes on local ancestry can reduce statistical power by up to 72%. This finding is especially pronounced in the presence of allele frequency differentiation. We replicate simulation results using 4,327 African-European admixed genomes from the UK Biobank for 12 traits to find that for most significant SNPs, HetLanc is not large enough for GWASs to benefit from modeling heterogeneity in this way.
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Affiliation(s)
- Rachel Mester
- Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Kangcheng Hou
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yi Ding
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Gillian Meeks
- Integrative Genetics and Genomics Graduate Group, University of California, Davis, Davis, CA 95616, USA
| | - Kathryn S Burch
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Arjun Bhattacharya
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Brenna M Henn
- Department of Anthropology, Center for Population Biology and the Genome Center, University of California, Davis, Davis, CA 95616, USA
| | - Bogdan Pasaniuc
- Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute of Precision Health, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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Kim HS, Shetty PB, Tsavachidis S, Dong J, Amos CI, El-Serag HB, Thrift AP. Admixture Mapping in African Americans Identifies New Risk Loci for HCV-Related Cirrhosis. Clin Gastroenterol Hepatol 2023; 21:1023-1030.e39. [PMID: 35680035 PMCID: PMC9722981 DOI: 10.1016/j.cgh.2022.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/03/2022] [Accepted: 05/06/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Cirrhosis is the main predisposing condition for hepatocellular carcinoma. Host genetic risk factors have been reported for cirrhosis; however, whether there is a genetic contribution to racial disparities in cirrhosis requires further investigation. METHODS We used an affected-only mapping by admixture linkage disequilibrium analysis to characterize the genetic risk of cirrhosis in 227 African American patients with cirrhosis genotyped at 19,804 ancestry-informative marker single nucleotide polymorphisms. We additionally performed analyses stratified by hepatitis C virus (HCV) infection status. To replicate our findings, we conducted a case-control analysis in an external study population (452 cases and 196 controls). RESULTS The mean age of patients was 63.3 years and 98.2% were male. Risk factors for cirrhosis included HCV infection (83.7%) and alcohol abuse (56.4%). In the admixture mapping analysis, we found that European ancestry on chromosome 2q21.1 and African ancestry on chromosome 6p21.2 were associated with increased risk of cirrhosis in African Americans. In the fine-mapping analysis, we identified regions near POTEKP on 2q21.1 (P = .0001) and DNAH8 on 6p21.2 (P = .0017) that were associated with cirrhosis. As the admixture peaks in the HCV-positive patients were the same as those in the overall group, findings in the analysis are reflective of the HCV-positive group. In the replication analysis, the results on chromosome 2 were not significant after adjusting for multiple comparisons, and we could not replicate the results on chromosome 6. CONCLUSIONS We used admixture mapping to identify novel genomic regions on 2q21.1 and 6p21.2 that may be associated with HCV-related cirrhosis risk in African Americans.
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Affiliation(s)
- Hyun-Seok Kim
- Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Priya B Shetty
- Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Spiridon Tsavachidis
- Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Jing Dong
- Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, Texas; Division of Hematology and Oncology, Department of Medicine, Cancer Center and Genomic Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Christopher I Amos
- Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, Texas; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas
| | - Hashem B El-Serag
- Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas; Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas
| | - Aaron P Thrift
- Section of Epidemiology and Population Sciences, Department of Medicine, Baylor College of Medicine, Houston, Texas; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas.
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3
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Mester R, Hou K, Ding Y, Meeks G, Burch KS, Bhattacharya A, Henn BM, Pasaniuc B. Impact of cross-ancestry genetic architecture on GWAS in admixed populations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524946. [PMID: 36747759 PMCID: PMC9900755 DOI: 10.1101/2023.01.20.524946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Genome-wide association studies (GWAS) have identified thousands of variants for disease risk. These studies have predominantly been conducted in individuals of European ancestries, which raises questions about their transferability to individuals of other ancestries. Of particular interest are admixed populations, usually defined as populations with recent ancestry from two or more continental sources. Admixed genomes contain segments of distinct ancestries that vary in composition across individuals in the population, allowing for the same allele to induce risk for disease on different ancestral backgrounds. This mosaicism raises unique challenges for GWAS in admixed populations, such as the need to correctly adjust for population stratification to balance type I error with statistical power. In this work we quantify the impact of differences in estimated allelic effect sizes for risk variants between ancestry backgrounds on association statistics. Specifically, while the possibility of estimated allelic effect-size heterogeneity by ancestry (HetLanc) can be modeled when performing GWAS in admixed populations, the extent of HetLanc needed to overcome the penalty from an additional degree of freedom in the association statistic has not been thoroughly quantified. Using extensive simulations of admixed genotypes and phenotypes we find that modeling HetLanc in its absence reduces statistical power by up to 72%. This finding is especially pronounced in the presence of allele frequency differentiation. We replicate simulation results using 4,327 African-European admixed genomes from the UK Biobank for 12 traits to find that for most significant SNPs HetLanc is not large enough for GWAS to benefit from modeling heterogeneity.
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Affiliation(s)
- Rachel Mester
- Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095 USA
| | - Kangcheng Hou
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, 90095 USA
| | - Yi Ding
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, 90095 USA
| | - Gillian Meeks
- Integrative Genetics and Genomics Graduate Group, University of California, Davis, Davis, CA, 95616 USA
| | - Kathryn S. Burch
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, 90095 USA
| | - Arjun Bhattacharya
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095 USA
| | - Brenna M. Henn
- Department of Anthropology, Center for Population Biology and the Genome Center, University of California, Davis, Davis, CA, 95616 USA
| | - Bogdan Pasaniuc
- Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095 USA
- Bioinformatics Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, 90095 USA
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095 USA
- Institute of Precision Health, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095 USA
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095 USA
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4
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Zhang C, Ostrom QT, Hansen HM, Gonzalez-Maya J, Hu D, Ziv E, Morimoto L, de Smith AJ, Muskens IS, Kline CN, Vaksman Z, Hakonarson H, Diskin SJ, Kruchko C, Barnholtz-Sloan JS, Ramaswamy V, Ali-Osman F, Bondy ML, Taylor MD, Metayer C, Wiemels JL, Walsh KM. European genetic ancestry associated with risk of childhood ependymoma. Neuro Oncol 2021; 22:1637-1646. [PMID: 32607579 DOI: 10.1093/neuonc/noaa130] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Ependymoma is a histologically defined central nervous system tumor most commonly occurring in childhood. Population-level incidence differences by race/ethnicity are observed, with individuals of European ancestry at highest risk. We aimed to determine whether extent of European genetic ancestry is associated with ependymoma risk in US populations. METHODS In a multi-ethnic study of Californian children (327 cases, 1970 controls), we estimated the proportions of European, African, and Native American ancestry among recently admixed Hispanic and African American subjects and estimated European admixture among non-Hispanic white subjects using genome-wide data. We tested whether genome-wide ancestry differences were associated with ependymoma risk and performed admixture mapping to identify associations with local ancestry. We also evaluated race/ethnicity-stratified ependymoma incidence data from the Central Brain Tumor Registry of the United States (CBTRUS). RESULTS CBTRUS data revealed that African American and Native American children have 33% and 36%, respectively, reduced incidence of ependymoma compared with non-Hispanic whites. In genetic analyses, a 20% increase in European ancestry was associated with a 1.31-fold higher odds of ependymoma among self-reported Hispanics and African Americans (95% CI: 1.08-1.59, Pmeta = 6.7 × 10-3). Additionally, eastern European ancestral substructure was associated with increased ependymoma risk in non-Hispanic whites (P = 0.030) and in Hispanics (P = 0.043). Admixture mapping revealed a peak at 20p13 associated with increased local European ancestry, and targeted fine-mapping identified a lead variant at rs6039499 near RSPO4 (odds ratio = 1.99; 95% CI: 1.45-2.73; P = 2.2 × 10-5) but which was not validated in an independent set of posterior fossa type A patients. CONCLUSIONS Interethnic differences in ependymoma risk are recapitulated in the genomic ancestry of ependymoma patients, implicating regions to target in future association studies.
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Affiliation(s)
- Chenan Zhang
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA
| | - Quinn T Ostrom
- Department of Medicine, Section of Epidemiology and Population Sciences, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas, USA.,Central Brain Tumor Registry of the United States, Hinsdale, Illinois, USA
| | - Helen M Hansen
- Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA
| | - Julio Gonzalez-Maya
- Department of Neurological Surgery, University of California San Francisco, San Francisco, California, USA
| | - Donglei Hu
- Division of General Internal Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Elad Ziv
- Division of General Internal Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Libby Morimoto
- School of Public Health, University of California Berkeley Berkeley, California, USA
| | - Adam J de Smith
- Center for Genetic Epidemiology, University of Southern California, Los Angeles, California, USA
| | - Ivo S Muskens
- Center for Genetic Epidemiology, University of Southern California, Los Angeles, California, USA
| | - Cassie N Kline
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, University of California San Francisco, San Francisco, California, USA.,Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Zalman Vaksman
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Hakon Hakonarson
- Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sharon J Diskin
- Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Children's Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Carol Kruchko
- Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Jill S Barnholtz-Sloan
- Department of Population and Quantitative Health Sciences and Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Vijay Ramaswamy
- The Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Francis Ali-Osman
- Department of Neurosurgery and Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, USA
| | - Melissa L Bondy
- Department of Medicine, Section of Epidemiology and Population Sciences, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas, USA
| | - Michael D Taylor
- The Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Catherine Metayer
- School of Public Health, University of California Berkeley Berkeley, California, USA
| | - Joseph L Wiemels
- Center for Genetic Epidemiology, University of Southern California, Los Angeles, California, USA
| | - Kyle M Walsh
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA.,Department of Neurosurgery and Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, USA
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5
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Colistro V, Mut P, Hidalgo PC, Carracedo A, Quintela I, Rojas-Martínez A, Sans M. Differential admixture in Latin American populations and its impact on the study of colorectal cancer. Genet Mol Biol 2020; 43:e20200143. [PMID: 33306774 PMCID: PMC7783724 DOI: 10.1590/1678-4685-gmb-2020-0143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 09/14/2020] [Indexed: 11/22/2022] Open
Abstract
Genome-wide association studies focused on searching genes responsible for
several diseases. Admixture mapping studies proposed a more efficient
alternative capable of detecting polymorphisms contributing with a small effect
on the disease risk. This method focuses on the higher values of linkage
disequilibrium in admixed populations. To test this, we analyzed 10 genomic
regions previously defined as related with colorectal cancer among nine
populations and studied the variation pattern of haplotypic structures and
heterozygosity values on seven categories of SNPs. Both analyses showed
differences among chromosomal regions and studied populations. Admixed
Latin-American samples generally show intermediate values. Heterozygosity of the
SNPs grouped in categories varies more in each gene than in each population.
African related populations have more blocks per chromosomal region, coherently
with their antiquity. In sum, some similarities were found among Latin American
populations, but each chromosomal region showed a particular behavior, despite
the fact that the study refers to genes and regions related with one particular
complex disease. This study strongly suggests the necessity of developing
statistical methods to deal with di- or tri-hybrid populations, as well as to
carefully analyze the different historic and demographic scenarios, and the
different characteristics of particular chromosomal regions and evolutionary
forces.
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Affiliation(s)
- Valentina Colistro
- Universidad de la República, Facultad de Medicina, Departamento de Métodos Cuantitativos, Montevideo, Uruguay
| | - Patricia Mut
- Universidad de la República, Facultad de Humanidades y Ciencias de la Educación, Departamento de Antropología Biológica, Montevideo, Uruguay
| | - Pedro C Hidalgo
- Universidad de la República, Centro Universitario de Tacuarembó, Polo de Desarrollo Universitario Diversidad Genética Humana, Tacuarembó, Uruguay
| | - Angel Carracedo
- Universidad de Santiago de Compostela, Centro Nacional de Genotipado (CEGEN), Spain.,Universidade de Santiago de Compostela, CIBER de Enfermedades Raras (CIBERER)-Instituto de Salud Carlos III, Grupo de Medicina Xenómica, Santiago de Compostela, Spain
| | - Inés Quintela
- Universidad de Santiago de Compostela, Centro Nacional de Genotipado (CEGEN), Spain
| | | | - Mónica Sans
- Universidad de la República, Facultad de Humanidades y Ciencias de la Educación, Departamento de Antropología Biológica, Montevideo, Uruguay
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6
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Fonseca H, da Silva TM, Saraiva M, Santolalla ML, Sant’Anna HP, Araujo NM, Lima NP, Rios R, Tarazona-Santos E, Horta BL, Cruz A, Barreto ML, Figueiredo CA. Genomic Regions 10q22.2, 17q21.31, and 2p23.1 Can Contribute to a Lower Lung Function in African Descent Populations. Genes (Basel) 2020; 11:E1047. [PMID: 32899814 PMCID: PMC7565985 DOI: 10.3390/genes11091047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/02/2022] Open
Abstract
Accumulated evidence supports the contribution of genetic factors in modulating airway function, especially ancestry. We investigated whether genetic polymorphisms can affect lung function in a mixed Brazilian child population using the admixture mapping strategy through RFMix software version 1.5.4 (Stanford University, Stanford, CA, USA), followed by fine mapping, to identify regions whereby local African or European ancestry is associated with lung function measured by the forced expiratory volume in the first second (FEV1)/forced vital capacity (FVC) ratio, an indicator of airway obstruction. The research cohort included 958 individuals aged 4 to 11 years enrolled in the SCAALA (Social Change, Asthma, Allergy in Latin America) Program. We identified that African ancestry at 17q21.31, 10q22.2, and 2p23.1 regions was associated with lower lung function measured by FEV1/FVC p < 1.9 × 10-4. In contrast, European ancestry at 17q21.31 showed an opposite effect. Fine mapping pointed out 5 single nucleotide polymorphisms (SNPs) also associated in our replication cohort (rs10999948, rs373831475, rs8068257, rs6744555, and rs1520322). Our results suggest that genomic regions associated with ancestry may contribute to differences in lung function measurements in African American children in Brazil replicated in a cohort of Brazilian adults. The analysis strategy used in this work is especially important for phenotypes, such as lung function, which has considerable disparities in terms of measurements across different populations.
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Affiliation(s)
- Héllen Fonseca
- Programa de Pós Graduação em Imunologia (PPGIm), Instituto de Ciências da Saúde, Universidade Federal da Bahia (UFBA), Salvador 40140-100, BA, Brazil; (H.F.); (M.S.); (R.R.)
| | - Thiago M. da Silva
- Departamento de Ciências Biológicas, Universidade Estadual do Sudoeste da Bahia, Jequié 45206-190, BA, Brazil;
| | - Mariana Saraiva
- Programa de Pós Graduação em Imunologia (PPGIm), Instituto de Ciências da Saúde, Universidade Federal da Bahia (UFBA), Salvador 40140-100, BA, Brazil; (H.F.); (M.S.); (R.R.)
| | - Meddly L. Santolalla
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil; (M.L.S.); (H.P.S.); (N.M.A.); (E.T.-S.)
| | - Hanaisa P. Sant’Anna
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil; (M.L.S.); (H.P.S.); (N.M.A.); (E.T.-S.)
| | - Nathalia M. Araujo
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil; (M.L.S.); (H.P.S.); (N.M.A.); (E.T.-S.)
| | - Natália P. Lima
- Programa de Pós-Graduação em Epidemiologia, Universidade Federal de Pelotas, Pelotas 96020-220, Rio Grande do Sul, Brazil; (N.P.L.); (B.L.H.)
| | - Raimon Rios
- Programa de Pós Graduação em Imunologia (PPGIm), Instituto de Ciências da Saúde, Universidade Federal da Bahia (UFBA), Salvador 40140-100, BA, Brazil; (H.F.); (M.S.); (R.R.)
| | - Eduardo Tarazona-Santos
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil; (M.L.S.); (H.P.S.); (N.M.A.); (E.T.-S.)
| | - Bernardo L Horta
- Programa de Pós-Graduação em Epidemiologia, Universidade Federal de Pelotas, Pelotas 96020-220, Rio Grande do Sul, Brazil; (N.P.L.); (B.L.H.)
| | - Alvaro Cruz
- ProAR, Faculdade de Medicina, Universidade Federal da Bahia (UFBA), Salvador 40060-330, BA, Brazil;
| | - Mauricio L. Barreto
- Centro de Integração de dados e Conhecimentos para Saúde (CIDACS), Fiocruz, Salvador 41745-715, BA, Brazil;
| | - Camila A. Figueiredo
- Departamento de Bio-Regulação, Instituto de Ciências da Saúde, Universidade Federal da Bahia (UFBA), Salvador 40110-902, BA, Brazil
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7
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Gouveia MH, Cesar CC, Santolalla ML, Anna HPS, Scliar MO, Leal TP, Araújo NM, Soares-Souza GB, Magalhães WCS, Mata IF, Ferri CP, Castro-Costa E, Mbulaiteye SM, Tishkoff SA, Shriner D, Rotimi CN, Tarazona-Santos E, Lima-Costa MF. Genetics of cognitive trajectory in Brazilians: 15 years of follow-up from the Bambuí-Epigen Cohort Study of Aging. Sci Rep 2019; 9:18085. [PMID: 31792241 PMCID: PMC6889148 DOI: 10.1038/s41598-019-53988-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/07/2019] [Indexed: 01/11/2023] Open
Abstract
Age-related cognitive decline (ACD) is the gradual process of decreasing of cognitive function over age. Most genetic risk factors for ACD have been identified in European populations and there are no reports in admixed Latin American individuals. We performed admixture mapping, genome-wide association analysis (GWAS), and fine-mapping to examine genetic factors associated with 15-year cognitive trajectory in 1,407 Brazilian older adults, comprising 14,956 Mini-Mental State Examination measures. Participants were enrolled as part of the Bambuí-Epigen Cohort Study of Aging. Our admixture mapping analysis identified a genomic region (3p24.2) in which increased Native American ancestry was significantly associated with faster ACD. Fine-mapping of this region identified a single nucleotide polymorphism (SNP) rs142380904 (β = -0.044, SE = 0.01, p = 7.5 × 10-5) associated with ACD. In addition, our GWAS identified 24 associated SNPs, most in genes previously reported to influence cognitive function. The top six associated SNPs accounted for 18.5% of the ACD variance in our data. Furthermore, our longitudinal study replicated previous GWAS hits for cognitive decline and Alzheimer's disease. Our 15-year longitudinal study identified both ancestry-specific and cosmopolitan genetic variants associated with ACD in Brazilians, highlighting the need for more trans-ancestry genomic studies, especially in underrepresented ethnic groups.
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Affiliation(s)
- Mateus H Gouveia
- Fundação Oswaldo Cruz, Instituto de Pesquisas René Rachou, Belo Horizonte, Brazil.
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil.
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
| | - Cibele C Cesar
- Universidade Federal de Minas Gerais, Faculdade de Ciências Econômicas, Belo Horizonte, Brazil
| | - Meddly L Santolalla
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Hanaisa P Sant Anna
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
- Melbourne Integrative Genomics, The University of Melbourne, Melbourne, VIC, 3052, Australia
| | - Marilia O Scliar
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Thiago P Leal
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Nathalia M Araújo
- Fundação Oswaldo Cruz, Instituto de Pesquisas René Rachou, Belo Horizonte, Brazil
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Giordano B Soares-Souza
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Wagner C S Magalhães
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
- Núcleo de Ensino e Pesquisa - NEP, Instituto Mário Penna, Rua Gentios, Terceiro Andar, Belo Horizonte, Minas Gerais, 3052, Brazil
| | - Ignacio F Mata
- Lerner Research Institute, Genomic Medicine, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Cleusa P Ferri
- Universidade Federal de São Paulo, Department of Psychiatry, São Paulo, Brazil
| | - Erico Castro-Costa
- Fundação Oswaldo Cruz, Instituto de Pesquisas René Rachou, Belo Horizonte, Brazil
| | - Sam M Mbulaiteye
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sarah A Tishkoff
- Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Daniel Shriner
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Charles N Rotimi
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Eduardo Tarazona-Santos
- Departamento de Genética, Ecologia e Evolução, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
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LEI: A Novel Allele Frequency-Based Feature Selection Method for Multi-ancestry Admixed Populations. Sci Rep 2019; 9:11103. [PMID: 31366927 PMCID: PMC6668412 DOI: 10.1038/s41598-019-47012-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 07/03/2019] [Indexed: 12/22/2022] Open
Abstract
Next-generation sequencing technologies now make it possible to sequence and genotype hundreds of thousands of genetic markers across the human genome. Selection of informative markers for the comprehensive characterization of individual genomic makeup using a high dimensional genomics dataset has become a common practice in evolutionary biology and human genetics. Although several feature selection approaches exist to determine the ancestry proportion in two-way admixed populations including African Americans, there are limited statistical tools developed for the feature selection approaches in three-way admixed populations (including Latino populations). Herein, we present a new likelihood-based feature selection method called Lancaster Estimator of Independence (LEI) that utilizes allele frequency information to prioritize the most informative features useful to determine ancestry proportion from multiple ancestral populations in admixed individuals. The ability of LEI to leverage summary-level statistics from allele frequency data, thereby avoiding the many restrictions (and big data issues) that can accompany access to individual-level genotype data, is appealing to minimize the computation and time-consuming ancestry inference in an admixed population. We compared our allele-frequency based approach with genotype-based approach in estimating admixed proportions in three-way admixed population scenarios. Our results showed ancestry estimates using the top-ranked features from LEI were comparable with the estimates using features from genotype-based methods in three-way admixed population. We provide an easy-to-use R code to assist researchers in using the LEI tool to develop allele frequency-based informative features to conduct admixture mapping studies from mixed samples of multiple ancestry origin.
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9
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Qin H, Zhao J, Zhu X. Identifying Rare Variant Associations in Admixed Populations. Sci Rep 2019; 9:5458. [PMID: 30931973 PMCID: PMC6443736 DOI: 10.1038/s41598-019-41845-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 03/12/2019] [Indexed: 12/27/2022] Open
Abstract
An admixed population and its ancestral populations bear different burdens of a complex disease. The ancestral populations may have different haplotypes of deleterious alleles and thus ancestry-gene interaction can influence disease risk in the admixed population. Among admixed individuals, deleterious haplotypes and their ancestries are dependent and can provide non-redundant association information. Herein we propose a local ancestry boosted sum test (LABST) for identifying chromosomal blocks that harbor rare variants but have no ancestry switches. For such a stable ancestral block, our LABST exploits ancestry-gene interaction and the number of rare alleles therein. Under the null of no genetic association, the test statistic asymptotically follows a chi-square distribution with one degree of freedom (1-df). Our LABST properly controlled type I error rates under extensive simulations, suggesting that the asymptotic approximation was accurate for the null distribution of the test statistic. In terms of power for identifying rare variant associations, our LABST uniformly outperformed several famed methods under four important modes of disease genetics over a large range of relative risks. In conclusion, exploiting ancestry-gene interaction can boost statistical power for rare variant association mapping in admixed populations.
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Affiliation(s)
- Huaizhen Qin
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, 32611, USA
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, New Orleans, LA, 70112, USA
| | - Jinying Zhao
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, 32611, USA
| | - Xiaofeng Zhu
- Department of Population and Quantitative Health Sciences, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, Ohio, 44106, USA.
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Grinde KE, Brown LA, Reiner AP, Thornton TA, Browning SR. Genome-wide Significance Thresholds for Admixture Mapping Studies. Am J Hum Genet 2019; 104:454-465. [PMID: 30773276 PMCID: PMC6407497 DOI: 10.1016/j.ajhg.2019.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/17/2019] [Indexed: 01/25/2023] Open
Abstract
Admixture mapping studies have become more common in recent years, due in part to technological advances and growing international efforts to increase the diversity of genetic studies. However, many open questions remain about appropriate implementation of admixture mapping studies, including how best to control for multiple testing, particularly in the presence of population structure. In this study, we develop a theoretical framework to characterize the correlation of local ancestry and admixture mapping test statistics in admixed populations with contributions from any number of ancestral populations and arbitrary population structure. Based on this framework, we develop an analytical approach for obtaining genome-wide significance thresholds for admixture mapping studies. We validate our approach via analysis of simulated traits with real genotype data for 8,064 unrelated African American and 3,425 Hispanic/Latina women from the Women's Health Initiative SNP Health Association Resource (WHI SHARe). In an application to these WHI SHARe data, our approach yields genome-wide significant p value thresholds of 2.1 × 10-5 and 4.5 × 10-6 for admixture mapping studies in the African American and Hispanic/Latina cohorts, respectively. Compared to other commonly used multiple testing correction procedures, our method is fast, easy to implement (using our publicly available R package), and controls the family-wise error rate even in structured populations. Importantly, we note that the appropriate admixture mapping significance threshold depends on the number of ancestral populations, generations since admixture, and population structure of the sample; as a result, significance thresholds are not, in general, transferable across studies.
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Affiliation(s)
- Kelsey E Grinde
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA.
| | - Lisa A Brown
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA; Seattle Genetics, Bothell, WA 98021, USA
| | - Alexander P Reiner
- Department of Epidemiology, University of Washington, Seattle, WA 98195, USA; Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Timothy A Thornton
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
| | - Sharon R Browning
- Department of Biostatistics, University of Washington, Seattle, WA 98195, USA
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11
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Esposito U, Das R, Syed S, Pirooznia M, Elhaik E. Ancient Ancestry Informative Markers for Identifying Fine-Scale Ancient Population Structure in Eurasians. Genes (Basel) 2018; 9:E625. [PMID: 30545160 PMCID: PMC6316245 DOI: 10.3390/genes9120625] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/05/2018] [Accepted: 12/10/2018] [Indexed: 12/23/2022] Open
Abstract
The rapid accumulation of ancient human genomes from various areas and time periods potentially enables the expansion of studies of biodiversity, biogeography, forensics, population history, and epidemiology into past populations. However, most ancient DNA (aDNA) data were generated through microarrays designed for modern-day populations, which are known to misrepresent the population structure. Past studies addressed these problems by using ancestry informative markers (AIMs). It is, thereby, unclear whether AIMs derived from contemporary human genomes can capture ancient population structures, and whether AIM-finding methods are applicable to aDNA, provided that the high missingness rates in ancient-and oftentimes haploid-DNA can also distort the population structure. Here, we define ancient AIMs (aAIMs) and develop a framework to evaluate established and novel AIM-finding methods in identifying the most informative markers. We show that aAIMs identified by a novel principal component analysis (PCA)-based method outperform all of the competing methods in classifying ancient individuals into populations and identifying admixed individuals. In some cases, predictions made using the aAIMs were more accurate than those made with a complete marker set. We discuss the features of the ancient Eurasian population structure and strategies to identify aAIMs. This work informs the design of single nucleotide polymorphism (SNP) microarrays and the interpretation of aDNA results, which enables a population-wide testing of primordialist theories.
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Affiliation(s)
- Umberto Esposito
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
| | - Ranajit Das
- Manipal University, Manipal Centre for Natural Sciences (MCNS), Manipal, Karnataka, 576104, India.
| | - Syakir Syed
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
| | - Mehdi Pirooznia
- Bioinformatics and Computational Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA .
| | - Eran Elhaik
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
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Shendre A, Wiener HW, Irvin MR, Aouizerat BE, Overton ET, Lazar J, Liu C, Hodis HN, Limdi NA, Weber KM, Gange SJ, Zhi D, Floris-Moore MA, Ofotokun I, Qi Q, Hanna DB, Kaplan RC, Shrestha S. Genome-wide admixture and association study of subclinical atherosclerosis in the Women's Interagency HIV Study (WIHS). PLoS One 2017; 12:e0188725. [PMID: 29206233 PMCID: PMC5714351 DOI: 10.1371/journal.pone.0188725] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/12/2017] [Indexed: 12/20/2022] Open
Abstract
Cardiovascular disease (CVD) is a major comorbidity among HIV-infected individuals. Common carotid artery intima-media thickness (cCIMT) is a valid and reliable subclinical measure of atherosclerosis and is known to predict CVD. We performed genome-wide association (GWA) and admixture analysis among 682 HIV-positive and 288 HIV-negative Black, non-Hispanic women from the Women’s Interagency HIV study (WIHS) cohort using a combined and stratified analysis approach. We found some suggestive associations but none of the SNPs reached genome-wide statistical significance in our GWAS analysis. The top GWAS SNPs were rs2280828 in the region intergenic to mediator complex subunit 30 and exostosin glycosyltransferase 1 (MED30 | EXT1) among all women, rs2907092 in the catenin delta 2 (CTNND2) gene among HIV-positive women, and rs7529733 in the region intergenic to family with sequence similarity 5, member C and regulator of G-protein signaling 18 (FAM5C | RGS18) genes among HIV-negative women. The most significant local European ancestry associations were in the region intergenic to the zinc finger and SCAN domain containing 5D gene and NADH: ubiquinone oxidoreductase complex assembly factor 1 (ZSCAN5D | NDUF1) pseudogene on chromosome 19 among all women, in the region intergenic to vomeronasal 1 receptor 6 pseudogene and zinc finger protein 845 (VN1R6P | ZNF845) gene on chromosome 19 among HIV-positive women, and in the region intergenic to the SEC23-interacting protein and phosphatidic acid phosphatase type 2 domain containing 1A (SEC23IP | PPAPDC1A) genes located on chromosome 10 among HIV-negative women. A number of previously identified SNP associations with cCIMT were also observed and included rs2572204 in the ryanodine receptor 3 (RYR3) and an admixture region in the secretion-regulating guanine nucleotide exchange factor (SERGEF) gene. We report several SNPs and gene regions in the GWAS and admixture analysis, some of which are common across HIV-positive and HIV-negative women as demonstrated using meta-analysis, and also across the two analytic approaches (i.e., GWA and admixture). These findings suggest that local European ancestry plays an important role in genetic associations of cCIMT among black women from WIHS along with other environmental factors that are related to CVD and may also be triggered by HIV. These findings warrant confirmation in independent samples.
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Affiliation(s)
- Aditi Shendre
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Howard W. Wiener
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Marguerite R. Irvin
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Bradley E. Aouizerat
- Bluestone Center for Clinical Research, New York University, New York, New York, United States of America
- Department of Oral and Maxillofacial Surgery, New York University, New York, New York, United States of America
| | - Edgar T. Overton
- Division of Infectious Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jason Lazar
- Department of Medicine, State University of New York, Downstate Medical Center, Brooklyn, New York, United States of America
| | - Chenglong Liu
- Department of Medicine, Georgetown University Medical Center, Washington, DC, United States of America
| | - Howard N. Hodis
- Atherosclerosis Research Unit, University of Southern California, Los Angeles, California, United States of America
| | - Nita A. Limdi
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Kathleen M. Weber
- Cook County Health and Hospital System/Hektoen Institute of Medicine, Chicago, Illnois, United States of America
| | - Stephen J. Gange
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Degui Zhi
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Michelle A. Floris-Moore
- Division of Infectious Diseases, Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Ighovwerha Ofotokun
- Department of Medicine/Infectious Diseases, Emory University, and Grady Healthcare System, Atlanta, Georgia, United States of America
| | - Qibin Qi
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - David B. Hanna
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Robert C. Kaplan
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Sadeep Shrestha
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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13
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Admixture mapping in the Hispanic Community Health Study/Study of Latinos reveals regions of genetic associations with blood pressure traits. PLoS One 2017; 12:e0188400. [PMID: 29155883 PMCID: PMC5695820 DOI: 10.1371/journal.pone.0188400] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/06/2017] [Indexed: 01/11/2023] Open
Abstract
Admixture mapping can be used to detect genetic association regions in admixed populations, such as Hispanics/Latinos, by estimating associations between local ancestry allele counts and the trait of interest. We performed admixture mapping of the blood pressure traits systolic and diastolic blood pressure (SBP, DBP), mean arterial pressure (MAP), and pulse pressure (PP), in a dataset of 12,116 participants from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Hispanics/Latinos have three predominant ancestral populations (European, African, and Amerindian), for each of which we separately tested local ancestry intervals across the genome. We identified four regions that were significantly associated with a blood pressure trait at the genome-wide admixture mapping level. A 6p21.31 Amerindian ancestry association region has multiple known associations, but none explained the admixture mapping signal. We identified variants that completely explained this signal. One of these variants had p-values of 0.02 (MAP) and 0.04 (SBP) in replication testing in Pima Indians. A 11q13.4 Amerindian ancestry association region spans a variant that was previously reported (p-value = 0.001) in a targeted association study of Blood Pressure (BP) traits and variants in the vitamin D pathway. There was no replication evidence supporting an association in the identified 17q25.3 Amerindian ancestry association region. For a region on 6p12.3, associated with African ancestry, we did not identify any candidate variants driving the association. It may be driven by rare variants. Whole genome sequence data may be necessary to fine map these association signals, which may contribute to disparities in BP traits between diverse populations.
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Abstract
Population of ethnic mixtures can be useful in genetic studies. Admixture mapping, or mapping by admixture linkage disequilibrium (MALD), is specially developed for admixed populations and can supplement traditional genome-wide association analyses in the search for genetic variants underlying complex traits. Admixture mapping tests the association between a trait and locus-specific ancestries. The locus-specific ancestries are in linkage disequilibrium (LD), which is generated by an admixture process between genetically distinct ancestral populations. Because of the highly correlated-locus specific ancestries, admixture mapping performs many fewer independent tests across the genome than current genome-wide association analysis. Therefore, admixture mapping can be more powerful because it reduces the penalty due to multiple tests. In this chapter, we introduce the theory behind admixture mapping and explain how to conduct the analysis in practice.
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15
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Thakur N, White MJ, Burchard EG. Race and Ethnicity. Respir Med 2017. [DOI: 10.1007/978-3-319-43447-6_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Vásquez-Loarte T, Trubnykova M, Guio H. Genetic association meta-analysis: a new classification to assess ethnicity using the association of MCP-1 -2518 polymorphism and tuberculosis susceptibility as a model. BMC Genet 2015; 16:128. [PMID: 26518714 PMCID: PMC4627623 DOI: 10.1186/s12863-015-0280-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 10/12/2015] [Indexed: 12/15/2022] Open
Abstract
Background In meta-analyses of genetic association studies, ancestry and ethnicity are not accurately investigated. Ethnicity is usually classified using conventional race/ethnic categories or continental groupings even though they could introduce bias increasing heterogeneity between and within studies; thus decreasing the external validity of the results. In this study, we performed a meta-analysis using a novel ethnic classification system to test the association between MCP-1 -2518 polymorphism and pulmonary tuberculosis. Our new classification considers genetic distance, migration and linguistic origins, which will increase homogeneity within ethnic groups. Methods We included thirteen studies from three continents (Asia, Africa and Latin America) and considered seven ethnic groups (West Africa, South Africa, Saharan Africa, East Asia, South Asia, Persia and Latin America). Results The results were compared to the continental group classification. We found a significant association between MCP-1 -2518 polymorphism and TB susceptibility only in the East Asian and Latin American groups (OR 3.47, P = 0.08; OR 2.73, P = 0.02). This association is not observed in other ethnic groups that are usually considered in the Asian group, such as India and Persia, or in the African group. Conclusions There is an association between MCP-1 -2518 polymorphism and TB susceptibility only in the East Asian and Latin American groups. We suggest the use of our new ethnic classification in future meta-analysis of genetic association studies when ancestry markers are not available. This new classification increases homogeneity for certain ethnic groups compared to the continental classification. We recommend considering previous data about migration, linguistics and genetic distance when classifying ethnicity in further studies.
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Affiliation(s)
- Tania Vásquez-Loarte
- Laboratorio de Biotecnología y Biología Molecular, Instituto Nacional de Salud, Avenida Defensores del, Morro 2268, Lima 9, Peru.
| | - Milana Trubnykova
- Laboratorio de Biotecnología y Biología Molecular, Instituto Nacional de Salud, Avenida Defensores del, Morro 2268, Lima 9, Peru.
| | - Heinner Guio
- Laboratorio de Biotecnología y Biología Molecular, Instituto Nacional de Salud, Avenida Defensores del, Morro 2268, Lima 9, Peru.
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Chen W, Ren C, Qin H, Archer KJ, Ouyang W, Liu N, Chen X, Luo X, Zhu X, Sun S, Gao G. A Generalized Sequential Bonferroni Procedure for GWAS in Admixed Populations Incorporating Admixture Mapping Information into Association Tests. Hum Hered 2015; 79:80-92. [PMID: 26087776 DOI: 10.1159/000381474] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 03/09/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To develop effective methods for GWAS in admixed populations such as African Americans. METHODS We show that, when testing the null hypothesis that the test SNP is not in background linkage disequilibrium with the causal variants, several existing methods cannot control well the family-wise error rate (FWER) in the strong sense in GWAS. These existing methods include association tests adjusting for global ancestry and joint association tests that combine statistics from admixture mapping tests and association tests that correct for local ancestry. Furthermore, we describe a generalized sequential Bonferroni (smooth-GSB) procedure for GWAS that incorporates smoothed weights calculated from admixture mapping tests into association tests that correct for local ancestry. We have applied the smooth-GSB procedure to analyses of GWAS data on American Africans from the Atherosclerosis Risk in Communities (ARIC) Study. RESULTS Our simulation studies indicate that the smooth-GSB procedure not only control the FWER, but also improves statistical power compared with association tests correcting for local ancestry. CONCLUSION The smooth-GSB procedure can result in a better performance than several existing methods for GWAS in admixed populations.
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Affiliation(s)
- Wenan Chen
- Department of Biostatistics, Virginia Commonwealth University, Richmond, Va., USA
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Shetty PB, Tang H, Feng T, Tayo B, Morrison AC, Kardia SLR, Hanis CL, Arnett DK, Hunt SC, Boerwinkle E, Rao DC, Cooper RS, Risch N, Zhu X. Variants for HDL-C, LDL-C, and triglycerides identified from admixture mapping and fine-mapping analysis in African American families. CIRCULATION. CARDIOVASCULAR GENETICS 2015; 8:106-13. [PMID: 25552592 PMCID: PMC4378661 DOI: 10.1161/circgenetics.114.000481] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Admixture mapping of lipids was followed-up by family-based association analysis to identify variants for cardiovascular disease in African Americans. METHODS AND RESULTS The present study conducted admixture mapping analysis for total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. The analysis was performed in 1905 unrelated African American subjects from the National Heart, Lung and Blood Institute's Family Blood Pressure Program (FBPP). Regions showing admixture evidence were followed-up with family-based association analysis in 3556 African American subjects from the FBPP. The admixture mapping and family-based association analyses were adjusted for age, age(2), sex, body mass index, and genome-wide mean ancestry to minimize the confounding caused by population stratification. Regions that were suggestive of local ancestry association evidence were found on chromosomes 7 (low-density lipoprotein cholesterol), 8 (high-density lipoprotein cholesterol), 14 (triglycerides), and 19 (total cholesterol and triglycerides). In the fine-mapping analysis, 52 939 single-nucleotide polymorphisms (SNPs) were tested and 11 SNPs (8 independent SNPs) showed nominal significant association with high-density lipoprotein cholesterol (2 SNPs), low-density lipoprotein cholesterol (4 SNPs), and triglycerides (5 SNPs). The family data were used in the fine-mapping to identify SNPs that showed novel associations with lipids and regions, including genes with known associations for cardiovascular disease. CONCLUSIONS This study identified regions on chromosomes 7, 8, 14, and 19 and 11 SNPs from the fine-mapping analysis that were associated with high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides for further studies of cardiovascular disease in African Americans.
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Affiliation(s)
- Priya B Shetty
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Hua Tang
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Tao Feng
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Bamidele Tayo
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Alanna C Morrison
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Sharon L R Kardia
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Craig L Hanis
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Donna K Arnett
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Steven C Hunt
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Eric Boerwinkle
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Dabeeru C Rao
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Richard S Cooper
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Neil Risch
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.)
| | - Xiaofeng Zhu
- From the Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH (P.B.S., T.F., X.Z.); Department of Genetics, Stanford University School of Medicine, Stanford, CA (H.T.); Department of Public Health Sciences, Loyola University of Chicago Stritch School of Medicine, Maywood, IL (B.T., R.S.C.); Division of Epidemiology, Human Genetics and Environmental Sciences, The University of Texas Health Science Center at Houston School of Public Health (A.C.M., C.L.H., E.B.); Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor (S.L.R.K.); Department of Epidemiology, University of Alabama at Birmingham School of Public Health (D.K.A.); Cardiovascular Genetics Division, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City (S.C.H.); Division of Biostatistics, Washington University in St. Louis School of Medicine, St. Louis, MO (D.C. Rao); and Department of Epidemiology and Biostatistics, University of California, San Francisco (N.R.).
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19
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Parker MM, Foreman MG, Abel HJ, Mathias RA, Hetmanski JB, Crapo JD, Silverman EK, Beaty TH. Admixture mapping identifies a quantitative trait locus associated with FEV1/FVC in the COPDGene Study. Genet Epidemiol 2014; 38:652-9. [PMID: 25112515 DOI: 10.1002/gepi.21847] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Revised: 06/30/2014] [Accepted: 07/03/2014] [Indexed: 12/31/2022]
Abstract
African Americans are admixed with genetic contributions from European and African ancestral populations. Admixture mapping leverages this information to map genes influencing differential disease risk across populations. We performed admixture and association mapping in 3,300 African American current or former smokers from the COPDGene Study. We analyzed estimated local ancestry and SNP genotype information to identify regions associated with FEV1 /FVC, the ratio of forced expiratory volume in one second to forced vital capacity, measured by spirometry performed after bronchodilator administration. Global African ancestry inversely associated with FEV1 /FVC (P = 0.035). Genome-wide admixture analysis, controlling for age, gender, body mass index, current smoking status, pack-years smoked, and four principal components summarizing the genetic background of African Americans in the COPDGene Study, identified a region on chromosome 12q14.1 associated with FEV1 /FVC (P = 2.1 × 10(-6) ) when regressed on local ancestry. Allelic association in this region of chromosome 12 identified an intronic variant in FAM19A2 (rs348644) as associated with FEV1 /FVC (P = 1.76 × 10(-6) ). By combining admixture and association mapping, a marker on chromosome 12q14.1 was identified as being associated with reduced FEV1 /FVC ratio among African Americans in the COPDGene Study.
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Affiliation(s)
- Margaret M Parker
- Department of Epidemiology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland, United States of America
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20
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Brown R, Pasaniuc B. Enhanced methods for local ancestry assignment in sequenced admixed individuals. PLoS Comput Biol 2014; 10:e1003555. [PMID: 24743331 PMCID: PMC3990492 DOI: 10.1371/journal.pcbi.1003555] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 02/10/2014] [Indexed: 01/22/2023] Open
Abstract
Inferring the ancestry at each locus in the genome of recently admixed individuals (e.g., Latino Americans) plays a major role in medical and population genetic inferences, ranging from finding disease-risk loci, to inferring recombination rates, to mapping missing contigs in the human genome. Although many methods for local ancestry inference have been proposed, most are designed for use with genotyping arrays and fail to make use of the full spectrum of data available from sequencing. In addition, current haplotype-based approaches are very computationally demanding, requiring large computational time for moderately large sample sizes. Here we present new methods for local ancestry inference that leverage continent-specific variants (CSVs) to attain increased performance over existing approaches in sequenced admixed genomes. A key feature of our approach is that it incorporates the admixed genomes themselves jointly with public datasets, such as 1000 Genomes, to improve the accuracy of CSV calling. We use simulations to show that our approach attains accuracy similar to widely used computationally intensive haplotype-based approaches with large decreases in runtime. Most importantly, we show that our method recovers comparable local ancestries, as the 1000 Genomes consensus local ancestry calls in the real admixed individuals from the 1000 Genomes Project. We extend our approach to account for low-coverage sequencing and show that accurate local ancestry inference can be attained at low sequencing coverage. Finally, we generalize CSVs to sub-continental population-specific variants (sCSVs) and show that in some cases it is possible to determine the sub-continental ancestry for short chromosomal segments on the basis of sCSVs. Advances in sequencing technologies are dramatically changing the volume and type of data collected in genetic studies. Although most genetic studies so far have focused on individuals of European ancestry, recent studies are increasingly being performed in individuals of admixed ancestry (i.e., with recent ancestors from multiple continents, e.g., Latino Americans). A key component in such studies is the accurate inference of continental ancestry at each segment in the genome of these individuals. In this work we present accurate and robust methods that use continent-specific variants (i.e., genetic variants observed only in individuals of a given continent), now readily accessible through sequencing technology, to perform extremely fast and accurate inference of the ancestral origin of each genomic segment in recently admixed individuals.
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Affiliation(s)
- Robert Brown
- Bioinformatics Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Pathology and Laboratory Medicine, Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (RB); (BP)
| | - Bogdan Pasaniuc
- Bioinformatics Interdepartmental Program, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Pathology and Laboratory Medicine, Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail: (RB); (BP)
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21
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Bensen JT, Xu Z, McKeigue PM, Smith GJ, Fontham ET, Mohler JL, Taylor JA. Admixture mapping of prostate cancer in African Americans participating in the North Carolina-Louisiana Prostate Cancer Project (PCaP). Prostate 2014; 74:1-9. [PMID: 24037755 PMCID: PMC3934014 DOI: 10.1002/pros.22722] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/22/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND Few genetic risk factors have been uncovered that contribute specifically to the racial disparity in prostate cancer (CaP) observed in African Americans (AA). With the advent of ancestry informative marker (AIM) single nucleotide polymorphism (SNP) panels and powerful genetic strategies such as mapping by admixture linkage disequilibrium (MALD) it is possible to discover genes that underlie ethnic variation in disease risk. METHODS One thousand one hundred thirty AA CaP cases enrolled in the North Carolina-Louisiana Prostate Cancer Project (PCaP) were genotyped using a 1,509 AIM SNP panel. MALD was performed using ADMIXMAP to test for linkage between CaP risk and ancestry estimates at each AIM SNP. RESULTS The largest increase of African ancestry was observed at marker rs12543473 (P = 0.0011), located on chromosome 8q24.21, and the greatest excess of European ancestry was observed at marker rs10768140 (P = 0.0004) at chromosome 11p13. CONCLUSIONS The study confirmed the 8q24 risk loci and identified a novel genomic region on 11p13 that is associated with CaP risk. These findings should be replicated in larger AA populations and combined with fine mapping data to further refine the novel 11p13 CaP risk loci.
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Affiliation(s)
- Jeannette T. Bensen
- Department of Epidemiology University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7435
- Lineberger Comprehensive Cancer Center University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7435
| | - Zongli Xu
- Epidemiology Branch National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
| | - Paul M. McKeigue
- Center for Population Health Sciences, University of Edinburgh Medical School, Tevoit Place, Edinburgh , United Kingdom
| | - Gary J. Smith
- Department of Urology, Roswell Park Cancer Institute, Buffalo, New York 14263
| | - Elizabeth T.H. Fontham
- School of Public Health, Louisiana State University Health Science Center, New Orleans, Louisiana 70112
| | - James L. Mohler
- Lineberger Comprehensive Cancer Center University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7435
- Department of Surgery, Division of Urology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7435
- Department of Urology, Roswell Park Cancer Institute, Buffalo, New York 14263
- Department of Urology, University of Buffalo School of Medicine and Biotechnology, Buffalo, New York, 14214
| | - Jack A. Taylor
- Epidemiology Branch National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
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