Genomic history of coastal societies from eastern South America

Sambaqui (shellmound) societies are among the most intriguing archaeological phenomena in pre-colonial South America, extending from approximately 8,000 to 1,000 years before present (yr BP) across 3,000 km on the Atlantic coast. However, little is known about their connection to early Holocene hunter-gatherers, how this may have contributed to different historical pathways and the processes through which late Holocene ceramists came to rule the coast shortly before European contact. To contribute to our understanding of the population history of indigenous societies on the eastern coast of South America, we produced genome-wide data from 34 ancient individuals as early as 10,000 yr BP from four different regions in Brazil. Early Holocene hunter-gatherers were found to lack shared genetic drift among themselves and with later populations from eastern South America, suggesting that they derived from a common radiation and did not contribute substantially to later coastal groups. Our analyses show genetic heterogeneity among contemporaneous Sambaqui groups from the southeastern and southern Brazilian coast, contrary to the similarity expressed in the archaeological record. The complex history of intercultural contact between inland horticulturists and coastal populations becomes genetically evident during the final horizon of Sambaqui societies, from around 2,200 yr BP, corroborating evidence of cultural change.

Reconstructing the Deep Population History of Central and South America

We report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least ∼9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America. One affected the Central Andes by ∼4,200 years ago, while the other explains an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. However, this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions.

Dentes intencionalmente modificados e etnicidade em cemitérios do Brasil Colônia e Império

A modificação intencional dos dentes foi muito difundida na África, vindo com escravos para a América. No Brasil foram encontradas em alguns sítios arqueológicos, sendo aqui estudadas em dois cemitérios históricos do Brasil: Pretos Novos, no Rio de Janeiro (único cemitério de um mercado de escravos na América), e cemitérios da antiga Sé de Salvador. Entre 570 dentes (30 indivíduos) dos Pretos Novos foram encontrados 13 dentes modificados. Entre 3181 dentes da Sé (62 enterros primários do séc. XVIII, e número indeterminado de re-deposições de outros períodos) foram encontrados 122 dentes modificados. Sua análise resultou em 13 tipos de modificações, a maior parte nos incisivos centrais superiores, e 10 tipos de arcos dentários modificados, evidenciando-se a técnica de percussão e lascamento dos dentes na maior parte dos casos. O achado de diferentes estilos de modificações sugere diferentes origens geográficas para os escravos do Rio e Salvador, o que é consistente com os dados históricos. No adro da Sé, a proximidade de enterros com modificações dentárias semelhantes sugere laços étnicos ou sociais, talvez de parentesco, entre os mortos.