Genetic composition of a Brazilian population: the footprint of the Gold Cycle

Abstract

ABSTRACT. Ancestry-informative markers (AIMs) are powerful tools for inferring the genetic composition of admixed populations. In this study, we determined the genetic ancestry of the Ouro Preto (Brazil) population and evaluated the association between ancestry and self-reported skin color. The genetic ancestry of 189 children Genetic composition of a Brazilian population and adolescents was estimated by genotyping 15 AIMs. The estimate of population admixture was determined using the Bayesian Markov Chain Monte Carlo (MCMC) method implemented in two different programs (STRUCTURE and ADMIXMAP). Volunteers self-reported their skin colors. The European ancestry contribution ranged from 0.503 to 0.539, the African contribution ranged from 0.333 to 0.425, and the Amerindian component ranged from 0.04 to 0.164. The relative contributions of African (P < 0.016) and European (P < 0.011) ancestry differed significantly among skin color groups, except between black and dark-brown groups. The population of Ouro Preto has a higher contribution of African ancestry compared to the mean for the southeast region of Brazil. Therefore, extrapolating the African ancestry contribution for southeastern Brazil to the Ouro Preto population would underestimate the actual value for this city. We also showed that selfreported skin color could be appropriate for describing the genetic structure of this particular population.

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

“…4,5,7,[22][23][24] In contrast, this paper is only one of many showing that Brazil can exhibit marked population structure, and self-identified skin color is generally consistent with the dominant or relative ancestral contribution. 6,8,[25][26][27][28][29] In this study, for both cities, blacks were twice as African as others in the surrounding population and whites more European, whereas the browns were intermediate. However, within localities, the designation of skin color may be relative to the ancestral mixture of one's neighbors.…”

Genetic Ancestry Is Associated With Systolic Blood Pressure and Glucose in Brazilian Children and Adolescents

“…To conduct this study, we used the highest cutoff point value of the AIMs (65%), which provided a reasonable number of individuals per ancestries groups. We believe that this cutoff value is appropriate because it is greater than the average value of the European AIMs described for Ouro Preto's population (50.3-53.9%) [18], and is the average of which is observed to southeastern Brazilian population (55.2-79.9%) [5,[22][23][24]. Although the prevalence of obesity, type 2 diabetes, and hypertension differs between ethnic groups, there are few correlation studies between genetic ancestry and risk phenotypes for these diseases.…”

“…The mean of three blood pressure measurements was considered. Using the data of predetermined genetic ancestry for this same population sample [18], we subdivided the sample of individuals into two groups: 1) predominantly African (PAFR) and 2) predominantly European (PEUR), according to the predominance in proportion of AIMs (≥ 65%) of each African or European parental population, respectively. The third group (predominantly mixed (PMIX)) was composed by a single individual who presented ≥ 65% of Amerindian AIMs and by all individuals who showed no predominance of any of the markers (< 65% of the all ancestral AIMs).…”

“…2016;6(6):167-171 tistics (IBGE) conducted in 2010 show that the city's population is composed of 14.4% black, according to the classification of self-reported skin color [17]. Previous studies of genetic ancestry revealed that the African genetic contribution is even greater in this population, accounting for 33.3% [18]. Additionally, the population is marked by a high prevalence of excess weight and obesity in adults (30% overweight and 11.9% obese), in children and adolescents (8.7% overweight and 6.2% obese) [19,20], and high morbidity (27.5%) due to diseases related to the circulatory system [17].…”

Estimativa da ancestralidade em Antropologia Forense por meio do software \"AncesTrees\" em medidas cranianas de uma amostra brasileira

“…Aferir erros de medição é crucial para atestar a repetibilidade e reprodutibilidade do método testado e assim assegurar a confiabilidade dos resultados obtidos (CORRON et. al., 2017) (LINS et al, 2011;QUEIROZ et al, 2013;PENA et al, 2009), e outros contrários a essa ligação (PARRA et al, 2003;PIMENTA et al, 2006 WRIGHT, R. Detection of likely ancestry using CRANID. In: OXENHAM, M (Ed).…”