USP study unravels Brazil’s ancient genetic history and demystifies theories of double migration in South America
Brazilian researchers have mastered all the stages of the technique for extracting and sequencing ancient DNA – a molecule found in biological material such as that from archaeological excavations, in remains thousands of years old.
The process for sequentially sequencing the ancient molecule, normally found in bone fragments, was developed by Swedish biologist Svante Pääbo, winner of the 2022 Nobel Prize in Physiology and Medicine for his discoveries about the genome of extinct hominids and human evolution.
It was at the Max Planck Institute of Evolutionary Anthropology, in Leipzig (Germany), where Pääbo is director of genetics, that Brazilian researcher Tiago Ferraz developed his doctorate, learned and brought mastery of the technique to USP (University of São Paulo).
In Germany, Tiago Ferraz was responsible for the ancient DNA sequencing process that resulted in the article Genomic History of Coastal Societies from Eastern South America (Genomic History of the Coastal Societies of Eastern South America), published in Nature Ecology & Evolution magazine.
Ferraz did, from the extraction of bone dust, where the material with old DNA is retained, to the analysis of the data and the interpretation of the results.
The senior researcher at the MAE (Museum of Archeology and Ethnology) at USP, André Menezes Strauss, was the senior researcher, and Tiago Ferraz was the first author. It was carried out in partnership with researchers from the Senckenberg Center for Human Evolution and Palaeoenvironment from the University of Tübingen, Germany.
“This is a work that has a very important institutional role: it is the 1st time that a team led by a Brazilian, which involved so many institutions, managed to publish a high-impact article in the field of archaeogenetics”says Strauss.
The research was based on extracting the genome of 34 samples, up to 10,000 years old, from 4 different regions of the east coast of Brazil, such as the Cabeçuda, Capelinha, Cubatão, Limão, Jabuticabeira, Kaingang, Palmeiras Xingu, Pedra do Alexandre and Vau sites. Unite. Among the material analyzed is Luzio, the oldest skeleton in São Paulo, around 13,000 years old.
According to André Strauss, the technique, now mastered by Brazilian researchers, was decisive in deciphering one of the enigmas of national archeology: these ancient coastal populations that inhabited what is now the Brazilian coast, called sambaquieiros, ancestors of the current indigenous people, belonged to only one biological group or 2 or more distinct peoples?
“Genetic analysis showed that this hypothesis [de serem povos distintos], was wrong. Genetic data shows that they descended from the same ancestral population, which populated 16,000 years ago. [onde hoje é o Brasil]as well as any indigenous group in Brazil or America”stresses Strauss.
One of the theories, now called into question by archeogenetics, advocated that the continent had been colonized by two waves of Homo sapiens coming from Asia. The 1st migratory wave would have occurred 14,000 years ago, with individuals with non-Mongoloid morphology, similar to current Australians and Africans, but who would not have left descendants here. The 2nd wave would have entered 12,000 years ago and its members would have the characteristic physical type of Asians, from which modern Indians would derive.
The result of the recent study, which used the sequencing of ancient DNA, shows, however, that there were not two migrations. “[Não houve migrações separadas da Ásia para cá], what we have are intracontinental migrations: people come here from the Andes, come from North America, from South America, but these are already local processes. These great migrations, the genetic data, contrary to what was imagined until now, show that it was a single migration from Asia”emphasizes Strauss.
Laboratory at USP
Trained for 2 years at the Max Planck Institute, in Germany, a world reference on ancient DNA, researcher Tiago Ferraz now hopes that, by the end of 2023, USP’s Laboratory of Archeology and Environmental and Evolutionary Anthropology, the 1st laboratory of archeogenetics in country, is fully operational. The space was built in collaboration with the Max Planck Institute.
“With their help, we were able to set up this space. Ancient DNA samples are difficult to extract because they require a physical structure, a laboratory with positive pressure, without external contact with contaminating DNA. A rigid system of sample processing and material decontamination is required”he says.
The researcher says that, with the laboratory functioning in its entirety, the sequencing of ancient DNA will be able to be carried out in Brazil, without depending on foreign structures. “We are in a space adaptation phase, we have been dealing with several technical, bureaucratic issues, in order to keep this space working in fact”account. “We are in the final touches to finally be able to inaugurate the space and actually work on it. Have a more intense work routine”.
The first intention, according to the researcher, is to train local researchers to generate archeogenetic data in loco. “Since we brought this technique to Brazil, we are going to implement it here, do it locally, sequence the individuals, sequence the ancient DNA here in Brazil, train people to work with it and develop this research group”.
With information from Brazil Agency.