Dataset Information

The correlation between ancestry and color in two cities of Northeast Brazil with contrasting ethnic compositions.

ABSTRACT: The degree of admixture in Brazil between historically isolated populations is complex and geographically variable. Studies differ as to what the genetic and phenotypic consequences of this mixing have been. In Northeastern Brazil, we enrolled 522 residents of Salvador and 620 of Fortaleza whose distributions of self-declared color were comparable to those in the national census. Using the program Structure and principal components analysis there was a clear correlation between biogeographic ancestry and categories of skin color. This correlation with African ancestry was stronger in Salvador (r=0.585; P<0.001) than in Fortaleza (r=0.236; P<0.001). In Fortaleza, although self-declared blacks had a greater proportion of European ancestry, they had more African ancestry than the other categories. When the populations were analyzed without pseudoancestors, as in some studies, the relationship of 'race' to genetic ancestry tended to diffuse or disappear. The inclusion of different African populations also influenced ancestry estimates. The percentage of unlinked ancestry informative markers in linkage disequilibrium, a measure of population structure, was 3-5 times higher in both Brazilian populations than expected by chance. We propose that certain methods, ascertainment bias and population history of the specific populations surveyed can result in failure to demonstrate a correlation between skin color and genetic ancestry. Population structure in Brazil has important implications for genetic studies, but genetic ancestry is irrelevant for how individuals are treated in society, their health, their income or their inclusion. These track more closely with perceived skin color than genetic ancestry.

SUBMITTER: Magalhaes da Silva T

PROVIDER: S-EPMC4463503 | biostudies-other | 2015 Jul

REPOSITORIES: biostudies-other

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The correlation between ancestry and color in two cities of Northeast Brazil with contrasting ethnic compositions.

Magalhães da Silva Thiago T Sandhya Rani M R MR de Oliveira Costa Gustavo Nunes GN Figueiredo Maria A MA Melo Paulo S PS Nascimento João F JF Molyneaux Neil D ND Barreto Maurício L ML Reis Mitermayer G MG Teixeira M Glória MG Blanton Ronald E RE

European journal of human genetics : EJHG 20141008 7

The degree of admixture in Brazil between historically isolated populations is complex and geographically variable. Studies differ as to what the genetic and phenotypic consequences of this mixing have been. In Northeastern Brazil, we enrolled 522 residents of Salvador and 620 of Fortaleza whose distributions of self-declared color were comparable to those in the national census. Using the program Structure and principal components analysis there was a clear correlation between biogeographic anc ...[more]

PMID: 25293718

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Project description:ObjectiveTo study the magnitude and direction of city-level racial and ethnic differences in poverty and education to characterise health equity and social determinants of health in California cities.DesignWe used data from the American Community Survey, United States Census Bureau, 2006-2010, and calculated differences in the prevalence of poverty and low educational attainment in adults by race/ethnicity and by census tracts within California cities. For race/ethnicity comparisons, when the referent group (p2) to calculate the difference (p1-p2) was the non-Hispanic White population (considered a historically advantaged group), a positive difference was considered a health inequity. Differences with a non-White reference group were considered health disparities.SettingCities of the State of California, USA.ResultsWithin-city differences in the prevalence of poverty and low educational attainment disfavoured Black and Latinos compared with Whites in over 78% of the cities. Compared with Whites, the median within-city poverty difference was 7.0% for Latinos and 6.2% for Blacks. For education, median within-city difference was 26.6% for Latinos compared with Whites. In a small, but not negligible proportion of cities, historically disadvantaged race/ethnicity groups had better social determinants of health outcomes than Whites. The median difference between the highest and lowest census tracts within cities was 14.3% for poverty and 15.7% for low educational attainment. Overall city poverty rate was weakly, but positively correlated with within-city racial/ethnic differences.ConclusionsDisparities and inequities are widespread in California. Local health departments can use these findings to partner with cities in their jurisdiction and design strategies to reduce racial, ethnic and geographic differences in economic and educational outcomes. These analytic methods could be used in an ongoing surveillance system to monitor these determinants of health.

Dataset Information

The correlation between ancestry and color in two cities of Northeast Brazil with contrasting ethnic compositions.

Publications

The correlation between ancestry and color in two cities of Northeast Brazil with contrasting ethnic compositions.

Similar Datasets

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