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Sun B, Wen YF, Culhane-Pera KA, Lo M, Straka RJ. Pharmacogenomic variabilities in geo-ancestral subpopulations and their clinical implications: Results of collaborations with Hmong in the United States. Front Genet 2023; 13:1070236. [PMID: 36685861 PMCID: PMC9845584 DOI: 10.3389/fgene.2022.1070236] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/07/2022] [Indexed: 01/06/2023] Open
Abstract
Underrepresentation of subpopulations within geo-ancestral groups engaged in research can exacerbate health disparities and impair progress toward personalized medicine. This is particularly important when implementing pharmacogenomics which uses genomic-based sources of variability to guide medication selection and dosing. This mini-review focuses on pharmacogenomic findings with Hmong in the United States and their potential clinical implications. By actively engaging Hmong community in pharmacogenomic-based research, several clinically relevant differences in allele frequencies were observed within key pharmacogenes such as CYP2C9 and CYP2C19 in Hmong compared to those in either East Asians or Europeans. Additionally, using state-of-the-art genome sequencing approaches, Hmong appear to possess novel genetic variants within CYP2D6, a critical pharmacogene affecting pharmacokinetics of a broad range of medications. The allele frequency differences and novel alleles in Hmong have translational impact and real-world clinical consequences. For example, Hmong patients exhibited a lower warfarin stable dose requirement compared to East Asian patients. This was predicted based on Hmong's unique genetic and non-genetic factors and confirmed using real-world data from clinical practice settings. By presenting evidence of the genetic uniqueness and its translational impact within subpopulations, such as the Hmong, we hope to inspire greater inclusion of other geo-ancestrally underrepresented subpopulations in pharmacogenomic-based research.
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Affiliation(s)
- Boguang Sun
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, United States
| | - Ya-Feng Wen
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, United States
| | | | - Muaj Lo
- Minnesota Community Care, St. Paul, MN, United States
| | - Robert J. Straka
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, MN, United States,*Correspondence: Robert J. Straka,
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Sun B, Wen YF, Culhane-Pera KA, Lo M, Xiong T, Lee K, Peng K, Thyagarajan B, Bishop JR, Zierhut H, Straka RJ. Differences in Predicted Warfarin Dosing Requirements Between Hmong and East Asians Using Genotype-Based Dosing Algorithms. Pharmacotherapy 2020; 41:265-276. [PMID: 33202062 DOI: 10.1002/phar.2487] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
INTRODUCTION Warfarin's narrow therapeutic index and high variability in dosage requirements make dosage selection critical. Genetic factors are known to impact warfarin dosage selection. The Hmong are a unique Asian subpopulation numbering over 278,000 in the United States whose participation in genetics-based research is virtually nonexistent. The translational significance of early reports of warfarin pharmacogene differences in Hmong has not been evaluated. OBJECTIVES (i) To validate previously identified allele frequency differences relevant to warfarin dosing in Hmong versus East Asians and (ii) to compare predicted warfarin sensitivity and maintenance doses between a Hmong population and an East Asian cohort. METHOD DNA collected from two independent cohorts (n=236 and n=198) of Hmong adults were genotyped for CYP2C9 (*2, *3), VKORC1 (G-1639A), and CYP4F2 (*3). Allele frequencies between the combined Hmong cohort (n=433) and East Asians (n=1165) from the 2009 International Warfarin Pharmacogenetics Consortium (IWPC) study were compared using a χ2 test. Percentages of Hmong and East Asian participants predicted to be very sensitive to warfarin were compared using a χ2 test, and the predicted mean warfarin maintenance dose was compared with a t test. RESULTS The allele frequencies of CYP2C9*3 in the combined Hmong cohort and CYP4F2*3 in the VIP-Hmong cohort are significantly different from those in East Asians (18.9% vs 3.0%, p<0.001 and 9.8% vs 22.1%, p<0.001, respectively). Comparing the combined Hmong cohort to the East Asian cohort, the percentage of participants predicted to be very sensitive to warfarin was significantly higher (28% vs 5%, p<0.01) and the mean predicted warfarin maintenance dose was significantly lower (19.8 vs 21.3 mg/week, p<0.001), respectively. CONCLUSION The unique allele frequencies related to warfarin when combined with nongenetic factors observed in the Hmong translate into clinically relevant differences in predicted maintenance dose requirements for Hmong versus East Asians.
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Affiliation(s)
- Boguang Sun
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ya-Feng Wen
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Muaj Lo
- Minnesota Community Care, St. Paul, Minnesota, USA
| | - Txia Xiong
- Minnesota Community Care, St. Paul, Minnesota, USA
| | - Koobmeej Lee
- Minnesota Community Care, St. Paul, Minnesota, USA
| | - Kerui Peng
- Titus Family Department of Clinical Pharmacy, School of Pharmacy, University of Southern California, Los Angeles, California, USA
| | - Bharat Thyagarajan
- Department of Laboratory Medicine and Pathology, School of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jeffrey R Bishop
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Heather Zierhut
- Department of Genetics, Cell Biology and Development, College of Biological Science, University of Minnesota, Minneapolis, Minnesota, USA
| | - Robert J Straka
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
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HLA-B*58:01 carrier status of Hmong in Minnesota: first in Hmong genotyping for prevalence of this biomarker of risk for severe cutaneous adverse reactions caused by allopurinol. Pharmacogenet Genomics 2020; 30:21-25. [DOI: 10.1097/fpc.0000000000000391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Merkhofer RM, O'Neill MB, Xiong D, Hernandez-Santos N, Dobson H, Fites JS, Shockey AC, Wuethrich M, Pepperell CS, Klein BS. Investigation of Genetic Susceptibility to Blastomycosis Reveals Interleukin-6 as a Potential Susceptibility Locus. mBio 2019; 10:e01224-19. [PMID: 31213563 PMCID: PMC6581865 DOI: 10.1128/mbio.01224-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 05/16/2019] [Indexed: 12/12/2022] Open
Abstract
Genetic differences are hypothesized to underlie ethnic disparities in incidence rates of the endemic systemic mycoses, including blastomycosis. Individuals of Hmong ancestry display elevated risk for this serious fungal infection. Here, we interrogated the genomes of Wisconsin (WI) Hmong blastomycosis patients using homozygosity mapping to uncover regions of the genome that are likely shared among the greater Hmong population and filtered for variants with high potential to affect disease susceptibility. This approach uncovered 113 candidate susceptibility variants, and among the most promising are those in genes involved in the interleukin-17 (IL-17) response. In particular, we identified 25 linked variants near the gene encoding IL-6 (IL6). We validated differences in cytokine production between Hmong and European volunteers and formally demonstrated a critical role for IL-6 in the development of adaptive immunity to Blastomyces dermatitidis Our findings suggest that the dysregulation of IL-17 responses underlies a recently reported and poorly understood ethnic health disparity.IMPORTANCE Blastomycosis is a potentially life-threatening infection caused by the fungus Blastomyces dermatitidis As with related fungal diseases, blastomycosis is noted to affect some populations more than others. These patterns of illness are often not related to predisposing conditions or exposure risks; thus, genetic differences are thought to underlie these health disparities. People of Hmong ancestry in Wisconsin are at elevated risk of blastomycosis compared to the general population. We studied the genetic codes of Hmong blastomycosis patients and identified candidate sites in their genomes that may explain their susceptibility to this infection. We further studied one particular region of the genome that is involved with the immune processes that fight B. dermatitidis Our work revealed population differences in the response to fungi. A better understanding of the genetic underpinnings of susceptibility to infectious diseases has broader implications for community health, especially in the paradigm of personalized medicine.
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Affiliation(s)
- Richard M Merkhofer
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Mary B O'Neill
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Donny Xiong
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Nydiaris Hernandez-Santos
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Hannah Dobson
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - J Scott Fites
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Abigail C Shockey
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Marcel Wuethrich
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Caitlin S Pepperell
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Bruce S Klein
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Biagini SA, Solé-Morata N, Matisoo-Smith E, Zalloua P, Comas D, Calafell F. People from Ibiza: an unexpected isolate in the Western Mediterranean. Eur J Hum Genet 2019; 27:941-951. [PMID: 30765884 DOI: 10.1038/s41431-019-0361-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 01/15/2019] [Accepted: 01/24/2019] [Indexed: 11/09/2022] Open
Abstract
In this study, we seek to understand and to correlate the genetic patterns observed in the population of the island of Ibiza in the Western Mediterranean basin with past events. Genome-wide genotypes of 189 samples representing 13 of 17 regions in Spain have been analyzed, in addition to 105 samples from the Levant, 157 samples from North Africa, and one ancient sample from the Phoenician Cas Molí site in Ibiza. Before the Catalans conquered the island in 1235 CE, Ibiza (Eivissa) had already been influenced by several cultures, starting with the Phoenicians, then the Carthaginians, followed by the Umayyads. The impact of these various cultures on the genetic structure of the islanders is still unexplored. Our results show a clear distinction between Ibiza and the rest of Spain. To investigate whether this was due to the Phoenician colonization or to more recent events, we compared the genomes of current Ibizans to that of an ancient Phoenician sample from Ibiza and to both modern Levantine and North African genomes. We did not identify any trace of Phoenician ancestry in the current Ibizans. Interestingly, the analysis of runs of homozygosity and changes in the effective population size through time support the idea that drift has shaped the genetic structure of current Ibizans. In addition to the small carrying capacity of the island, Ibiza experienced a series of dramatic demographic changes due to several instances of famine, war, malaria and plague that could have significantly contributed to its current genetic differentiation.
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Affiliation(s)
- Simone Andrea Biagini
- Departament de Ciències Experimentals i de la Salut, Institute of Evolutionary Biology (CSIC-UPF), Universitat Pompeu Fabra, Barcelona, Spain
| | - Neus Solé-Morata
- Departament de Ciències Experimentals i de la Salut, Institute of Evolutionary Biology (CSIC-UPF), Universitat Pompeu Fabra, Barcelona, Spain
| | | | - Pierre Zalloua
- School of Medicine, The Lebanese American University, Chouran, Beirut, Lebanon
| | - David Comas
- Departament de Ciències Experimentals i de la Salut, Institute of Evolutionary Biology (CSIC-UPF), Universitat Pompeu Fabra, Barcelona, Spain
| | - Francesc Calafell
- Departament de Ciències Experimentals i de la Salut, Institute of Evolutionary Biology (CSIC-UPF), Universitat Pompeu Fabra, Barcelona, Spain.
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Culhane-Pera KA, Moua M, Vue P, Xiaaj K, Lo MX, Straka RJ. Leaves imitate trees: Minnesota Hmong concepts of heredity and applications to genomics research. J Community Genet 2016; 8:23-34. [PMID: 27822876 DOI: 10.1007/s12687-016-0284-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/18/2016] [Indexed: 11/30/2022] Open
Abstract
Historically, Hmong refugees in the USA were distrustful of Western medicine, medicines, and medical research due to concerns about harm and experimentation. Current Hmong concerns about genomics research are not well known. Our research aims were to identify cultural and ethical issues about conducting genomic studies in the Hmong community. Using a community-based participatory action process, the West Side Hmong Genomics Research Board conducted a qualitative exploratory research study that included semistructured interviews with five Hmong key informants and five focus groups with 42 Hmong adults near Saint Paul, Minnesota. We used a thematic analysis approach to qualitatively analyze the data. Identified concepts of heredity included characteristics that are passed between the generations: physical features; character traits; some behaviors; some diseases; and probably not response to medicines, although individual variations to medicines are known. Most participants were willing to join genomic research projects to help themselves and community. Others refused to participate: they did not want to know future disease risk; did not want doctors to know their genes; did not trust doctors with their blood; and did not know if they would benefit from results. Ethically, many participants were in favor of confidentiality, but wanted to know their personal results; many were willing to agree to genetic storage of anonymous samples; all agreed with individual consent, not family or community consent; and none were concerned about social stigma from genetic testing about chronic diseases and medications. The Hmong Genomics Board will build upon these concepts to create, conduct, and evaluate culturally-appropriate genomic and pharmacogenomic research projects relevant to community interests.
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Affiliation(s)
| | - MaiKia Moua
- Benton County Health Services, 530 NW 27th St, Corvallis, OR, 97330, USA
| | - Pachia Vue
- University of Minnesota Medical Center-Fairview Campus, 2450 Riverside Ave, Minneapolis, MN, 55454, USA
| | - Kang Xiaaj
- West Side Community Health Services, 153 Cesar Chavez St, Saint Paul, MN, 55107, USA
| | - May Xia Lo
- Phalen Family Pharmacy, 1001 Johnson Parkway, St Paul, MN, 55106, USA
| | - Robert J Straka
- Department of Experimental and Clinical Pharmacology, College of Pharmacy University of Minnesota, 7-115 Weaver-Densford Hall, 308 Harvard St SE, Minneapolis, MN, 55455, USA
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GlobalFiler ® Express DNA amplification kit in South Africa: Extracting the past from the present. Forensic Sci Int Genet 2016; 24:194-201. [DOI: 10.1016/j.fsigen.2016.07.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 06/10/2016] [Accepted: 07/11/2016] [Indexed: 01/23/2023]
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Kutanan W, Srikummool M, Pittayaporn P, Seielstad M, Kangwanpong D, Kumar V, Prombanchachai T, Chantawannakul P. Admixed origin of the Kayah (Red Karen) in Northern Thailand revealed by biparental and paternal markers. Ann Hum Genet 2015; 79:108-21. [PMID: 25590861 DOI: 10.1111/ahg.12100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 11/27/2014] [Indexed: 11/27/2022]
Abstract
This study analyzes the autosomal short tandem repeats (STRs) variation and the presence of Y chromosomal haplogroups from 44 individuals of the Kayah or Red Karen (KA) in Northern Thailand. The results based on autosomal STRs indicated that the KA exhibited closer genetic relatedness to populations from adjacent regions in Southeast Asia (SEA) than populations from Northeast Asia (NEA) and Tibet. Moreover, an admixed origin of the KA forming three population groups was observed: NEA, Southern China, and Northern Thailand. The NEA populations made a minor genetic contribution to the KA, while the rest came from populations speaking Sino-Tibetan (ST) languages from Southern China and Tai-Kadai (TK) speaking groups from Northern Thailand. The presence of six paternal haplogroups, composed of dual haplogroups prevalent in NEA (NO, N, and D1) and SEA (O2 and O3) as well as the intermediate genetic position of the KA between the SEA and NEA also indicated an admixed origin of male KA lineages. Our genetic results thus agree with findings in linguistics that Karenic languages are ST languages that became heavily influenced by TK during their southward spread. A result of the Mongol invasions during the 13th century A.D. is one possible explanation for genetic contribution of NEA to the KA.
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Affiliation(s)
- Wibhu Kutanan
- Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand
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Bart G, Lenz S, Straka RJ, Brundage RC. Ethnic and genetic factors in methadone pharmacokinetics: a population pharmacokinetic study. Drug Alcohol Depend 2014; 145:185-93. [PMID: 25456329 PMCID: PMC4254688 DOI: 10.1016/j.drugalcdep.2014.10.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 10/16/2014] [Accepted: 10/16/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Treatment of opiate use disorders with methadone is complicated by wide interindividual variability in pharmacokinetics. To identify potentially contributing covariates in methadone pharmacokinetics, we used population pharmacokinetic modeling to estimate clearance (CL/F) and volume of distribution (V/F) for each methadone enantiomer in an ethnically diverse methadone maintained population. METHODS Plasma levels of the opiate-active R-methadone and opiate-inactive S-methadone were measured in 206 methadone maintained subjects approximately two and twenty-three hours after a daily oral dose of rac-methadone. A linear one-compartment population pharmacokinetic model with first-order conditional estimation with interaction (FOCE-I) was used to evaluate methadone CL/F and V/F. The influence of covariates on parameter estimates was evaluated using stepwise covariate modeling. Covariates included ethnicity, gender, weight, BMI, age, methadone dose, and 21 single nucleotide polymorphisms in genes implicated in methadone pharmacokinetics. RESULTS In the final model, for each enantiomer, Hmong ethnicity reduced CL/F by approximately 30% and the rs2032582 (ABCB1 2677G>T/A) GG genotype was associated with a 20% reduction in CL/F. The presence of the rs3745274 minor allele (CYP2B6 515G>T) reduced CL/F by up to 20% for S-methadone only. A smaller effect of age was noted on CL/F for R-methadone. CONCLUSION This is the first report showing the influence of the rs2032582 and rs3745274 variants on methadone pharmacokinetics rather than simply dose requirements or plasma levels. Population pharmacokinetics is a valuable method for identifying the influences on methadone pharmacokinetic variability.
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Affiliation(s)
- Gavin Bart
- Department of Medicine, Hennepin County Medical Center, 701 Park Avenue, Minneapolis, MN 55415, USA.
| | - Scott Lenz
- Minneapolis Medical Research Foundation, 914 S 8th St., Minneapolis, MN 55404, USA
| | - Robert J. Straka
- Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, 5-130 Weaver-Densford Hall, 308 Harvard Street SE, Minneapolis, MN 55455, USA
| | - Richard C. Brundage
- Department of Experimental and Clinical Pharmacology, University of Minnesota College of Pharmacy, 5-130 Weaver-Densford Hall, 308 Harvard Street SE, Minneapolis, MN 55455, USA
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Kutanan W, Kitpipit T, Phetpeng S, Thanakiatkrai P. Forensic STR loci reveal common genetic ancestry of the Thai-Malay Muslims and Thai Buddhists in the deep Southern region of Thailand. J Hum Genet 2014; 59:675-81. [PMID: 25339232 DOI: 10.1038/jhg.2014.93] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 09/17/2014] [Accepted: 09/17/2014] [Indexed: 11/09/2022]
Abstract
Among the people living in the five deep Southern Thai provinces, Thai-Malay Muslims (MUS) constitute the majority, while the remaining are Thai Buddhists (BUD). Cultural, linguistic and religious differences between these two populations have been previously reported. However, their biological relationship has never been investigated. In this study, we aimed to reveal the genetic structure and genetic affinity between MUS and BUD by analyzing 15 autosomal short tandem repeats. Both distance and model-based clustering methods showed significant genetic homogeneity between these two populations, suggesting a common biological ancestry. After Islamization in this region during the fourteenth century AD, gradual albeit nonstatistically significant genetic changes occurred within these two populations. Cultural barriers possibly influenced these genetic changes. MUS have closer admixture to Malaysian-Malay Muslims than BUD countrywide. Admixture proportions also support certain degree of genetic dissimilarity between the two studied populations, as shown by the unequal genetic contribution from Malaysian-Malay Muslims. Cultural transformation and recent minor genetic admixture are the likely processes that shaped the genetic structure of both MUS and BUD.
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Affiliation(s)
- Wibhu Kutanan
- Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand
| | - Thitika Kitpipit
- Forensic Science Program, Department of Applied Science, Faculty of Science, Prince of Songkla University, Songkhla, Thailand
| | - Sukanya Phetpeng
- DNA Analysis Center, Scientific Crime Detection Division 10, Royal Thai Police, Songkhla, Thailand
| | - Phuvadol Thanakiatkrai
- Forensic Science Program, Department of Applied Science, Faculty of Science, Prince of Songkla University, Songkhla, Thailand
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Wangkumhang P, Shaw PJ, Chaichoompu K, Ngamphiw C, Assawamakin A, Nuinoon M, Sripichai O, Svasti S, Fucharoen S, Praphanphoj V, Tongsima S. Insight into the peopling of Mainland Southeast Asia from Thai population genetic structure. PLoS One 2013; 8:e79522. [PMID: 24223962 PMCID: PMC3817124 DOI: 10.1371/journal.pone.0079522] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/23/2013] [Indexed: 12/22/2022] Open
Abstract
There is considerable ethno-linguistic and genetic variation among human populations in Asia, although tracing the origins of this diversity is complicated by migration events. Thailand is at the center of Mainland Southeast Asia (MSEA), a region within Asia that has not been extensively studied. Genetic substructure may exist in the Thai population, since waves of migration from southern China throughout its recent history may have contributed to substantial gene flow. Autosomal SNP data were collated for 438,503 markers from 992 Thai individuals. Using the available self-reported regional origin, four Thai subpopulations genetically distinct from each other and from other Asian populations were resolved by Neighbor-Joining analysis using a 41,569 marker subset. Using an independent Principal Components-based unsupervised clustering approach, four major MSEA subpopulations were resolved in which regional bias was apparent. A major ancestry component was common to these MSEA subpopulations and distinguishes them from other Asian subpopulations. On the other hand, these MSEA subpopulations were admixed with other ancestries, in particular one shared with Chinese. Subpopulation clustering using only Thai individuals and the complete marker set resolved four subpopulations, which are distributed differently across Thailand. A Sino-Thai subpopulation was concentrated in the Central region of Thailand, although this constituted a minority in an otherwise diverse region. Among the most highly differentiated markers which distinguish the Thai subpopulations, several map to regions known to affect phenotypic traits such as skin pigmentation and susceptibility to common diseases. The subpopulation patterns elucidated have important implications for evolutionary and medical genetics. The subpopulation structure within Thailand may reflect the contributions of different migrants throughout the history of MSEA. The information will also be important for genetic association studies to account for population-structure confounding effects.
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Affiliation(s)
- Pongsakorn Wangkumhang
- National Center for Genetic Engineering and Biotechnology (BioTeC), Khlong Luang, Pathum Thani, Thailand
- Inter-Department Program of Biomedical Sciences, Chulalongkorn University, Pathumwan, Bangkok, Thailand
| | - Philip James Shaw
- National Center for Genetic Engineering and Biotechnology (BioTeC), Khlong Luang, Pathum Thani, Thailand
| | - Kridsadakorn Chaichoompu
- National Center for Genetic Engineering and Biotechnology (BioTeC), Khlong Luang, Pathum Thani, Thailand
| | - Chumpol Ngamphiw
- National Center for Genetic Engineering and Biotechnology (BioTeC), Khlong Luang, Pathum Thani, Thailand
- Inter-Department Program of Biomedical Sciences, Chulalongkorn University, Pathumwan, Bangkok, Thailand
| | | | - Manit Nuinoon
- School of Allied Health Sciences and Public Health, Walailak University, Thai Buri, Nakhon Sri Thammarat, Thailand
| | - Orapan Sripichai
- Thalassemia Research Center, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Saovaros Svasti
- Thalassemia Research Center, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Suthat Fucharoen
- Thalassemia Research Center, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Verayuth Praphanphoj
- Center for Medical Genetics Research, Rajanukul Institute, Dindaeng, Bangkok, Thailand
| | - Sissades Tongsima
- National Center for Genetic Engineering and Biotechnology (BioTeC), Khlong Luang, Pathum Thani, Thailand
- * E-mail:
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Phillips CD, Hoffman JI, George JC, Suydam RS, Huebinger RM, Patton JC, Bickham JW. Molecular insights into the historic demography of bowhead whales: understanding the evolutionary basis of contemporary management practices. Ecol Evol 2012; 3:18-37. [PMID: 23403722 PMCID: PMC3568839 DOI: 10.1002/ece3.374] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/07/2012] [Accepted: 08/08/2012] [Indexed: 11/12/2022] Open
Abstract
Patterns of genetic variation observed within species reflect evolutionary histories that include signatures of past demography. Understanding the demographic component of species' history is fundamental to informed management because changes in effective population size affect response to environmental change and evolvability, the strength of genetic drift, and maintenance of genetic variability. Species experiencing anthropogenic population reductions provide valuable case studies for understanding the genetic response to demographic change because historic changes in the census size are often well documented. A classic example is the bowhead whale, Balaena mysticetus, which experienced dramatic population depletion due to commercial whaling in the late 19th and early 20th centuries. Consequently, we analyzed a large multi-marker dataset of bowhead whales using a variety of analytical methods, including extended Bayesian skyline analysis and approximate Bayesian computation, to characterize genetic signatures of both ancient and contemporary demographic histories. No genetic signature of recent population depletion was recovered through any analysis incorporating realistic mutation assumptions, probably due to the combined influences of long generation time, short bottleneck duration, and the magnitude of population depletion. In contrast, a robust signal of population expansion was detected around 70,000 years ago, followed by a population decline around 15,000 years ago. The timing of these events coincides to a historic glacial period and the onset of warming at the end of the last glacial maximum, respectively. By implication, climate driven long-term variation in Arctic Ocean productivity, rather than recent anthropogenic disturbance, appears to have been the primary driver of historic bowhead whale demography.
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Affiliation(s)
- C D Phillips
- Department of Biological Sciences, Texas Tech University Lubbock, Texas
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Abstract
The forensic genetics field is generating extensive population data on polymorphism of short tandem repeats (STR) markers in globally distributed samples. In this study we explored and quantified the informative power of these datasets to address issues related to human evolution and diversity, by using two online resources: an allele frequency dataset representing 141 populations summing up to almost 26 thousand individuals; a genotype dataset consisting of 42 populations and more than 11 thousand individuals. We show that the genetic relationships between populations based on forensic STRs are best explained by geography, as observed when analysing other worldwide datasets generated specifically to study human diversity. However, the global level of genetic differentiation between populations (as measured by a fixation index) is about half the value estimated with those other datasets, which contain a much higher number of markers but much less individuals. We suggest that the main factor explaining this difference is an ascertainment bias in forensics data resulting from the choice of markers for individual identification. We show that this choice results in average low variance of heterozygosity across world regions, and hence in low differentiation among populations. Thus, the forensic genetic markers currently produced for the purpose of individual assignment and identification allow the detection of the patterns of neutral genetic structure that characterize the human population but they do underestimate the levels of this genetic structure compared to the datasets of STRs (or other kinds of markers) generated specifically to study the diversity of human populations.
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Affiliation(s)
- Nuno M. Silva
- IPATIMUP (Instituto de Patologia e Imunologia Molecular da Universidade do Porto), Universidade do Porto, Porto, Portugal
| | - Luísa Pereira
- IPATIMUP (Instituto de Patologia e Imunologia Molecular da Universidade do Porto), Universidade do Porto, Porto, Portugal
- Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Estella S. Poloni
- Laboratory of Anthropology, Genetics and Peopling History, Department of Genetics and Evolution - Anthropology Unit, University of Geneva, Geneva, Switzerland
| | - Mathias Currat
- Laboratory of Anthropology, Genetics and Peopling History, Department of Genetics and Evolution - Anthropology Unit, University of Geneva, Geneva, Switzerland
- * E-mail:
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14
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Abstract
A new approach to assigning individuals to populations using genetic data is described. Most existing methods work by maximizing Hardy-Weinberg and linkage equilibrium within populations, neither of which will apply for many demographic histories. By including a demographic model, within a likelihood framework based on coalescent theory, we can jointly study demographic history and population assignment. Genealogies and population assignments are sampled from a posterior distribution using a general isolation-with-migration model for multiple populations. A measure of partition distance between assignments facilitates not only the summary of a posterior sample of assignments, but also the estimation of the posterior density for the demographic history. It is shown that joint estimates of assignment and demographic history are possible, including estimation of population phylogeny for samples from three populations. The new method is compared to results of a widely used assignment method, using simulated and published empirical data sets.
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15
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Listman JB, Malison RT, Sanichwankul K, Ittiwut C, Mutirangura A, Gelernter J. Southeast Asian origins of five Hill Tribe populations and correlation of genetic to linguistic relationships inferred with genome-wide SNP data. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2011; 144:300-8. [PMID: 20979205 DOI: 10.1002/ajpa.21408] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
In Thailand, the term Hill Tribe is used to describe populations whose members traditionally practice slash and burn agriculture and reside in the mountains. These tribes are thought to have migrated throughout Asia for up to 5,000 years, including migrations through Southern China and/or Southeast Asia. There have been continuous migrations southward from China into Thailand for approximately the past thousand years and the present geographic range of any given tribe straddles multiple political borders. As none of these populations have autochthonous scripts, written histories have until recently, been externally produced. Northern Asian, Tibetan, and Siberian origins of Hill Tribes have been proposed. All purport endogamy and have nonmutually intelligible languages. To test hypotheses regarding the geographic origins of these populations, relatedness and migrations among them and neighboring populations, and whether their genetic relationships correspond with their linguistic relationships, we analyzed 2,445 genome-wide SNP markers in 118 individuals from five Thai Hill Tribe populations (Akha, Hmong, Karen, Lahu, and Lisu), 90 individuals from majority Thai populations, and 826 individuals from Asian and Oceanean HGDP and HapMap populations using a Bayesian clustering method. Considering these results within the context of results ofrecent large-scale studies of Asian geographic genetic variation allows us to infer a shared Southeast Asian origin of these five Hill Tribe populations as well ancestry components that distinguish among them seen in successive levels of clustering. In addition, the inferred level of shared ancestry among the Hill Tribes corresponds well to relationships among their languages.
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Affiliation(s)
- J B Listman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA
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16
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Genetic affinity and admixture of northern Thai people along their migration route in northern Thailand: evidence from autosomal STR loci. J Hum Genet 2010; 56:130-7. [DOI: 10.1038/jhg.2010.135] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Kanthaswamy S, Satkoski J, Kou A, Malladi V, Glenn Smith D. Detecting signatures of inter-regional and inter-specific hybridization among the Chinese rhesus macaque specific pathogen-free (SPF) population using single nucleotide polymorphic (SNP) markers. J Med Primatol 2010; 39:252-65. [PMID: 20618591 DOI: 10.1111/j.1600-0684.2010.00430.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND While rates of gene flow between rhesus and longtail macaque populations near their hybrid zone in Indochina have been quantified elsewhere, this study demonstrates that the inter-specific introgression is not limited to the Indochinese hybrid zone but is more geographically widespread. METHODS Twelve rhesus and longtail macaque populations were analyzed using single nucleotide polymorphic (SNP) loci. RESULTS There is evidence for inter-specific admixture between Chinese rhesus and mainland longtails, with implications for genetic diversity both in the Chinese super-SPF population at the California National Primate Research Center and in other primate facilities. Eastern Chinese rhesus appeared more highly derived than western Chinese rhesus, and allele sharing between longtails and Chinese rhesus was not random with regard to geographic distance, but no significant nuclear genetic differences between eastern and western Chinese rhesus were detected among the 245 genic SNPs assayed. CONCLUSION The implications of this inter-specific admixture for the use of Chinese rhesus and mainland longtail in biomedical research should be considered.
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Affiliation(s)
- Sree Kanthaswamy
- Department of Anthropology, University of California-Davis, Davis, CA, USA.
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18
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Londin ER, Keller MA, Maista C, Smith G, Mamounas LA, Zhang R, Madore SJ, Gwinn K, Corriveau RA. CoAIMs: a cost-effective panel of ancestry informative markers for determining continental origins. PLoS One 2010; 5:e13443. [PMID: 20976178 PMCID: PMC2955551 DOI: 10.1371/journal.pone.0013443] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 09/19/2010] [Indexed: 12/14/2022] Open
Abstract
Background Genetic ancestry is known to impact outcomes of genotype-phenotype studies that are designed to identify risk for common diseases in human populations. Failure to control for population stratification due to genetic ancestry can significantly confound results of disease association studies. Moreover, ancestry is a critical factor in assessing lifetime risk of disease, and can play an important role in optimizing treatment. As modern medicine moves towards using personal genetic information for clinical applications, it is important to determine genetic ancestry in an accurate, cost-effective and efficient manner. Self-identified race is a common method used to track and control for population stratification; however, social constructs of race are not necessarily informative for genetic applications. The use of ancestry informative markers (AIMs) is a more accurate method for determining genetic ancestry for the purposes of population stratification. Methodology/Principal Findings Here we introduce a novel panel of 36 microsatellite (MSAT) AIMs that determines continental admixture proportions. This panel, which we have named Continental Ancestry Informative Markers or CoAIMs, consists of MSAT AIMs that were chosen based upon their measure of genetic variance (Fst), allele frequencies and their suitability for efficient genotyping. Genotype analysis using CoAIMs along with a Bayesian clustering method (STRUCTURE) is able to discern continental origins including Europe/Middle East (Caucasians), East Asia, Africa, Native America, and Oceania. In addition to determining continental ancestry for individuals without significant admixture, we applied CoAIMs to ascertain admixture proportions of individuals of self declared race. Conclusion/Significance CoAIMs can be used to efficiently and effectively determine continental admixture proportions in a sample set. The CoAIMs panel is a valuable resource for genetic researchers performing case-control genetic association studies, as it can control for the confounding effects of population stratification. The MSAT-based approach used here has potential for broad applicability as a cost effective tool toward determining admixture proportions.
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Affiliation(s)
- Eric R Londin
- Coriell Institute for Medical Research, Camden, New Jersey, United States of America.
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19
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Simms TM, Rodriguez CE, Rodriguez R, Herrera RJ. The genetic structure of populations from Haiti and Jamaica reflect divergent demographic histories. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2010; 142:49-66. [PMID: 19918989 DOI: 10.1002/ajpa.21194] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The West Indies represent an amalgamation of African, European and in some cases, East Asian sources, but the contributions from each ethnic group remain relatively unexplored from a genetic perspective. In the present study, we report, for the first time, allelic frequency data across the complete set of 15 autosomal STR loci for general collections from Haiti and Jamaica, which were subsequently used to examine the genetic diversity present in each island population. Our results indicate that although both Haiti and Jamaica display genetic affinities with the continental African collections, a stronger African signal is detected in Haiti than in Jamaica. Although only minimal contributions from non-African sources were observed in Haiti, Jamaica displays genetic input from both European and East Asian sources, an admixture profile similar to other New World collections of African descent analyzed in this report. The divergent genetic signatures present in these populations allude to the different migratory events of Africans, Europeans, and East Asians into the New World.
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Affiliation(s)
- Tanya M Simms
- Department of Molecular and Human Genetics, College of Medicine, Florida International University, Miami, FL 33199, USA
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20
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Listman JB, Hasin D, Kranzler HR, Malison RT, Mutirangura A, Sughondhabirom A, Aharonovich E, Spivak B, Gelernter J. Identification of population substructure among Jews using STR markers and dependence on reference populations included. BMC Genet 2010; 11:48. [PMID: 20546593 PMCID: PMC2896335 DOI: 10.1186/1471-2156-11-48] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 06/14/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Detecting population substructure is a critical issue for association studies of health behaviors and other traits. Whether inherent in the population or an artifact of marker choice, determining aspects of a population's genetic history as potential sources of substructure can aid in design of future genetic studies. Jewish populations, among which association studies are often conducted, have a known history of migrations. As a necessary step in understanding population structure to conduct valid association studies of health behaviors among Israeli Jews, we investigated genetic signatures of this history and quantified substructure to facilitate future investigations of these phenotypes in this population. RESULTS Using 32 autosomal STR markers and the program STRUCTURE, we differentiated between Ashkenazi (AJ, N = 135) and non-Ashkenazi (NAJ, N = 226) Jewish populations in the form of Northern and Southern geographic genetic components (AJ north 73%, south 23%, NAJ north 33%, south 60%). The ability to detect substructure within these closely related populations using a small STR panel was contingent on including additional samples representing major continental populations in the analyses. CONCLUSIONS Although clustering programs such as STRUCTURE are designed to assign proportions of ancestry to individuals without reference population information, when Jewish samples were analyzed in the absence of proxy parental populations, substructure within Jews was not detected. Generally, for samples with a given grandparental country of birth, STRUCTURE assignment values to Northern, Southern, African and Asian clusters agreed with mitochondrial DNA and Y-chromosomal data from previous studies as well as historical records of migration and intermarriage.
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Affiliation(s)
- Jennifer B Listman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
| | - Deborah Hasin
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, NY, USA
- New York State Psychiatric Institute, NY, USA
- Dept Epidemiology, Mailman School of Public Health, Columbia University, NY, USA
| | - Henry R Kranzler
- Departments of Psychiatry and Genetics and Developmental Biology, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Robert T Malison
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- VA Connecticut Healthcare System, West Haven Campus, West Haven, CT, USA
| | | | | | - Efrat Aharonovich
- Department of Psychiatry, Columbia University College of Physicians and Surgeons, NY, USA
| | - Baruch Spivak
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Joel Gelernter
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- VA Connecticut Healthcare System, West Haven Campus, West Haven, CT, USA
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT, USA
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21
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Amstadter AB, Koenen KC, Ruggiero KJ, Acierno R, Galea S, Kilpatrick DG, Gelernter J. NPY moderates the relation between hurricane exposure and generalized anxiety disorder in an epidemiologic sample of hurricane-exposed adults. Depress Anxiety 2010; 27:270-5. [PMID: 20037921 PMCID: PMC2879267 DOI: 10.1002/da.20648] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neuropeptide Y (NPY) has been found to be anxiolytic in animals and humans. A recent study found NPY expression to be inversely correlated with trait anxiety. We examined whether rs16147, a functional single nucleotide polymorphism in the promoter region of NPY, moderated the relationship between hurricane exposure and risk for generalized anxiety disorder (GAD) in an epidemiologic sample of adults living in areas affected by the 2004 Florida hurricanes. METHODS Data from this study comes from 616 adults from the 2004 Florida Hurricanes study who returned buccal DNA samples via mail. Selection of participants occurred via random digit-dial procedures. Participants were interviewed via telephone about hurricane exposure and post-hurricane GAD symptoms. The outcome measure was DSM-IV GAD diagnosis, assessed via structured interview. RESULTS Rs16147 in NPY was associated with increased risk of GAD diagnosis under conditions of high hurricane exposure (P<.01). This gene by environment interaction remained significant after adjustment for sex, ancestry (as determined by Bayesian clustering of genotypes), and age. CONCLUSIONS NPY rs16147 modifies risk of post-disaster GAD under conditions of high stressor (hurricane) exposure. This is the first demonstration of gene-environment interaction for this locus.
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Affiliation(s)
- Ananda B Amstadter
- Department of Psychiatry, Medical University of South Carolina, 67 President Street, Charleston, SC 29425, USA.
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22
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Amstadter AB, Koenen KC, Ruggiero KJ, Acierno R, Galea S, Kilpatrick DG, Gelernter J. Variation in RGS2 is associated with suicidal ideation in an epidemiological study of adults exposed to the 2004 Florida hurricanes. Arch Suicide Res 2009; 13:349-57. [PMID: 19813112 PMCID: PMC2760049 DOI: 10.1080/13811110903266541] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This study examined whether rs4606, a single nucleotide polymorphism (SNP) in the translated region at the 3' end of RGS2, was related to suicidal ideation in an epidemiologic sample of adults living in areas affected by the 2004 Florida hurricanes. An epidemiologic sample of residents of Florida was recruited via random digit-dial procedures after the 2004 Florida hurricanes; participants were interviewed about suicidal ideation, hurricane exposure, and social support. Participants who returned buccal DNA samples via mail (n = 607) were included here. Rs4606 in RGS2 was associated with increased symptoms of current suicidal ideation (p < 0.01). Each "C" allele was associated with 5.59 times increased risk of having current ideation. No gene-by-environment interactions were found, perhaps due to low power. RGS2 rs4606 is related to risk of current suicidal ideation in stressor-exposed adults.
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Affiliation(s)
- Ananda B Amstadter
- Department of Psychiatry and Behavioral Science, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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Ittiwut C, Listman J, Mutirangura A, Malison R, Covault J, Kranzler HR, Sughondhabirom A, Thavichachart N, Gelernter J. Interpopulation linkage disequilibrium patterns of GABRA2 and GABRG1 genes at the GABA cluster locus on human chromosome 4. Genomics 2007; 91:61-9. [PMID: 17976953 DOI: 10.1016/j.ygeno.2007.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Revised: 08/10/2007] [Accepted: 08/23/2007] [Indexed: 11/20/2022]
Abstract
GABRA2 and GABRG1, which encode the alpha-2 and gamma-1 subunits, respectively, of the GABA(A) receptor, are located in a cluster on chromosome 4p. The GABRA2 locus has been found to be associated with alcohol dependence in several studies, but no functional variant that can account for this association has been identified. To understand the reported associations, we sought to understand the linkage disequilibrium (LD) patterns and haplotype structures of these genes. With close intergenic distance, approximately 90 kb, it was anticipated that some markers might show intergenic LD. Variation in 13-SNP haplotype block structure was observed in five different populations: European American, African American, Chinese (Han and Thai), Thai, and Hmong. In the Hmong, a 280-kb region of considerably higher LD spans the intergenic region, whereas in other populations, there were two or more LD blocks that cross this region. These findings may aid in understanding the genetic association of this locus with alcohol dependence in several populations.
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Affiliation(s)
- Chupong Ittiwut
- Department of Psychiatry, Yale School of Medicine, New Haven, CT 06510, USA
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