Genetic Ancestry Reveals Historical Diversity of Formation Across Three Brazilian Communities of African Descent (Quilombos) in Central Brazil

TL;DR

This study explores the genetic diversity of three Brazilian quilombo communities, revealing how their histories of isolation and location influence their ancestry.

Contribution

The study provides new insights into the genetic ancestry of recently settled Central Brazilian quilombos, highlighting regional and sociodemographic variations.

Findings

Average African ancestry varied significantly among the three quilombo communities, with Kalunga having the highest at 63.17%.

Communities closer to urban areas showed higher European and Indigenous ancestry contributions.

The study reveals how historical and environmental factors shape the genetic makeup of quilombo populations.

Abstract

Characterized as relatively isolated communities, many Brazilian quilombos were formed during the period of slavery in Brazil when enslaved persons (most of African descent) ran away or were abandoned by their enslavers. Quilombos in Central Brazil, whose settlement was more recent due to the relative isolation of the region, remain understudied. To address this gap, this study estimated the genetic ancestry of three quilombo communities in Central Brazil.

A cross‐sectional study was performed among three Central Brazilian quilombos, Cocalinho (N = 54) and Pé do Morro (N = 58) located in the Brazilian state of Tocantins, and Kalunga (N = 132) located in the state of Goiás. Genetic ancestry was estimated from 61 Ancestry‐informative INDEL biallelic markers collected from blood samples and analyzed using STRUCTURE v 2.3. Statistical analyses were performed using SAS statistical software, v. 9.4.

The population demonstrated heterogeneous genetic admixture by quilombo. Average African admixture estimates were 36.75%, 29.82%, and 63.17% in Cocalinho (semirural), Pé do Morro (urban), and Kalunga (rural) communities, respectively. Indigenous and European ancestry contributions also varied by quilombo, with participants from the more recently populated quilombos and those living closest to urban areas having higher European and Indigenous genetic ancestry contributions.

This study demonstrates that quilombos comprise rich population histories shaped by culture, historical events, and sociodemographic and environmental interactions. By unraveling the genetic tapestry of Central Brazil's quilombos, this study contributes to a deeper understanding of Brazil's intricate social and historical landscape.

Figures