Virtual anthropology and archaeogenomics of pre-colonial Brazil

Abstract

Population dynamics, ancestry relationships, social organization and phenotypic traits are fundamental aspects of the indigenous bio-cultural past that can be studied by archaeology. Here we contribute to these topics through two new disciplines that complement each other: virtual anthropology and archaeogenomics. The following archaeological questions will be addressed: internal homogeneity and relationship with post-colonial Amerindians of groups associated with pottery of the Incised-Rim Tradition and of the Aratu Tradition, demographic origin of the non-agricultural chiefdoms of Marajó Island, presence of the australo-asiatic signal (i.e. Y population) among groups inhabiting the fluvial shell middens of the Guaporé region in the state of Rondônia (east Amazonia), populational structure in the coastal shell middens of South and Southeast Brazil, relationship of coastal and fluvial shell middens, demic implications of the arrival of ceramists to the coast by the end of the Holocene, consanguinity relationships between individuals integrating 'afinities groups' in shell middens of Santa Catarina, and the ancestry relationship between early Paleoamericans and late Amerindians. Virtual anthropology unites three-dimensional modeling and high-resolution geometric morphometrics. Beyond its analytical applications, virtual anthropology also introduces a new era in managing archaeological heritage. Skulls, petrous bone and teeth will be virtualized by computed tomographies from which three-dimensional models will be extracted. High-resolution geometric morphometrics will be used to access the morphological affinities of both crania and bone labyrinth. The cranium is a complex anatomical structure and therefore it is important to verify if previous studies based on linear measurements are confirmed by a high-resolution approach based on three-dimensional models. Facial reconstruction incorporating phenotypic estimations from archaeogenomic data will be produced based on retro-deformed three-dimensional cranial models. Patterns of morphological variation of the bony labyrinth contain information on micro-evolutionary processes. Resistant to the passage of time it allows morphological studies to include contexts with highly fragmented skeletons. This is the first time these analysis will be applied to Brazilian archaeological remains. Archaeogenomics will allow for a detailed characterization of the genetic constitution of pre-colonial Amerindians, estimation of past demographic parameters, dating of coalescence events, identification of consanguinity relationships, and to estimate phenotypic traits. Ancient mtDNA will be extracted in the first Brazilian laboratory exclusively dedicated to archaeogenomics that will be established in the Institute of Biosciences of São Paulo University in collaboration with the Max Planck Institute for the Science of Human History. Strontium isotopic analysis from dental enamel inform on geographic provenience and mobility patterns and will complement genetic and morphological data in the interpretation of past population dynamics. A solid chronological context will be provided by Bayesian modelling of radiocarbon dates obtained from non-contaminated collagen. Excavations focusing on spatiality of the site and three-dimensional modeling of relevant structures will be conducted in the single large shell midden in the state of Espírito Santo, state in which there are no archaeological skeletal remains with associated context, and in Pains, only region besides Lagoa Santa and Vale do Ribeira where skeletons directly dated to more than 9000 years are found. Geoarchaeological studies based on a micro-contextual approach will be conducted at both sites. An archaeological ethnography will be conducted in both localities aiming to establish the best way in which this research project can contribute with local communities and further action will be taken accordingly. (AU)