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Relating West African Ancestry and Genetic Admixture to Health Phenotypes in the Tobago Cohort Study population

Beresford, Ruel (2023) Relating West African Ancestry and Genetic Admixture to Health Phenotypes in the Tobago Cohort Study population. Master Essay, University of Pittsburgh.

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Background: Researchers from the University of Pittsburgh have been collecting genetic infor-mation from research participants on the Caribbean island of Tobago, along with health pheno-types, in a prospective cohort study since 2000. This essay’s goal is to use Tobago Health Study (THS) data to relate African ancestry and admixture to health traits. Specifically, this study exam-ines the health outcomes of grip strength, calf muscle area, density, and intermuscular fat to see if they are related to African ancestry.
Methods: The Tobagonian Single Nucleotide Polymorphism, specifically 119 Ancestry In-formative Markers (AIMs) data was converted into additive. The BCFTools suite in Unix was used to locate and pull down the same AIMs from specific continental superpopulations (African, Euro-pean, South Asian, East Asian, admixed Americans) and subpopulations comprising each super-population (e.g., Yoruba, Esan, Mende) from the 1000 Genomes Project Phase 3 data. The super-population data was merged with the THS data, and data was analyzed with a principal compo-nents analysis. Factor loadings were computed to estimate the genetic admixture (ancestry) of the THS men. These factor scores were then used as primary explanatory variables in linear regression and ANOVA models to predict the health outcomes of interest.
Results: The Afro-Tobagonian Study Population demonstrates predominantly African An-cestry, followed less prominently by European and South Asian Ancestry. Subpopulation analysis shows prominent levels of West African ancestry. Factor 1, higher levels of which reflect a higher proportion of African ancestry alleles, had a significant (p = 0.01), positive association with inter-muscular fat.
Conclusion: The Afro-Tobagonians unsurprisingly had primarily African ancestry, but the prominence of South Asian and European ancestry was somewhat novel. The prominence of Yo-ruba, Esan, and Mende ancestry was noteworthy. The relationship between intermuscular fat and African Ancestry substantiates what has been found in literature, and the positive dose response nature of the relationship is also intriguing and of public health relevance.


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Item Type: Other Thesis, Dissertation, or Long Paper (Master Essay)
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Beresford, Ruelreb169@pitt.edureb1690000000217826082
ContributionContributors NameEmailPitt UsernameORCID
Thesis advisorSantanasto, Adamajs51@pitt.eduajs51UNSPECIFIED
Committee MemberKenkre, Tanyakenkre@edc.pitt.edukenkretUNSPECIFIED
Committee MemberMinster, Ryanrminster@pitt.edurminsterUNSPECIFIED
Date: 4 January 2023
Date Type: Completion
Submission Date: 15 December 2022
Access Restriction: 2 year -- Restrict access to University of Pittsburgh for a period of 2 years.
Number of Pages: 63
Institution: University of Pittsburgh
Schools and Programs: School of Public Health > Epidemiology
Degree: MPH - Master of Public Health
Thesis Type: Master Essay
Refereed: Yes
Uncontrolled Keywords: Molecular Epidemiology Afro Caribbeans Afro Tobagonians Chronic Diseases Global Health bioinformatics
Date Deposited: 04 Jan 2023 14:41
Last Modified: 04 Jan 2023 14:41


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