Sunday , October 24 2021

A new face of South Americans – ScienceDaily


The history of the peoples of the Americas has just been redefined. The largest and the most comprehensive study ever made on the basis of fossilized DNA extracted from ancient human remains found on the continent, has confirmed the existence of a single population of ancestors for all Indian ethnic groups, past and present.

Over 17,000 years ago, this original contingent crossed the Bering Strait from Siberia to Alaska and began to populate Nowy Świat. Fossil DNA has an affinity between this migratory current and the populations of Siberia and northern China. In contrast to traditional theory, it had no connection with Africa or Australasia.

New research also reveals that when they settled in North America, the descendants of this ancient migratory stream split into two lines about 16,000 years ago.

Members of one line crossed the Panama Isthmus and populated South America in three different waves.

The first wave took place between 15,000 and 11,000 years ago. The second took place no more than 9,000 years ago. There are records of fossil fuels from both migrations throughout South America. The third wave is much newer, but its impact is limited, as it was 4 200 years ago. Its members settled in the Central Andes.

An article about this research has just been published in the journal Cell a group of 72 scientists from eight countries, affiliated with the University of São Paulo (USP) in Brazil, Harvard University in the United States and the Institute of Humanities in Max Planck in Germany.

According to the findings of the researchers, the line that traveled between north and south between 16,000 and 15,000 years ago belonged to the Clovis culture, named after a group of archaeological sites dug in the western United States and dated 13.511,000 years ago.

The Clovis culture was named when the flint was found in the 1930s at the Clovis site in New Mexico. Clovis sites have been identified in the United States and in Mexico and Central America. In North America, Clovis hunted for Pleistocene megafauna, such as gigantic laziness and mammoth. With the collapse of megafauna and its extinction 11,000 years ago, Clovis culture eventually disappeared. Long before, however, hunter-gatherers' gangs drove south to explore new hunting grounds. They settled in Central America, as evidenced by the 9,400-year-old human fossil DNA found in Belize and analyzed in the new study.

Later, perhaps during the hunt for herds of mastodons, Clovis hunter-gatherers crossed the Panama Isthmus and spread to South America, as evidenced by genetic records from burial sites in Brazil and Chile. This genetic evidence confirms well-known archaeological finds, such as the Monte Verde site in southern Chile, where people massacred the mastodons 14,800 years ago.

Among the many known places of Clovis, the only burial site associated with the Clovis tools is located in Montana, where the remains of the boy (Anzick-1) were found and date back to 12,600 years ago. The DNA extracted from these bones contains links to DNA from the skeletons of humans who lived between 10,000 and 9,000 years ago in caves near Lagoa Santa, Minas Gerais, Brazil. In other words, the people of Lagoa Santa were partial descendants of Clovis immigrants from North America.

"From a genetic point of view, the people of Lagoa Santa are descendants of the first Indians," said archaeologist André Menezes Strauss, who coordinated the Brazilian part of the research. Strauss is associated with the Museum of Archeology and Ethnology at the University of São Paulo (MAE-USP).

"Surprisingly, the members of this first South American line did not leave any identifiable descendants among today's Indians," he said. "About 9,000 years ago their DNA completely disappeared from the fossil samples and was replaced by DNA from the first migration wave, before the Clovis culture. All living Indian people are descendants of this first wave, we do not know why the human stock of Santa Laguna has disappeared."

One possible reason for the disappearance of DNA from the second migration is that it has been diluted in Indian DNA, who are descendants of the first wave and can not be identified by existing methods of genetic analysis.

According to Tábita Hünemeier, a geneticist at the Institute of Bioscience of the University of Sao Paulo (IB-USP), who participated in the study, "one of the main results of the study was to identify people Luzia as genetically related to the Clovis culture, which eliminates the idea of ​​two biological components and the possibility of that there were two migrations in America, one with African traits and the other with Asian traits. "

"The people of Luzia had to come from a migration wave from Beringia," she said, referring to the now-flooded Bering land bridge, which connected Siberia with Alaska during glaciation, when the sea level was lower.

"Molecular data suggest population substitution in South America from 9,000 years ago, the people of Luzia disappeared and were replaced by the Indians living today, although they both had a common origin in Beringia," said Hünemeier.

Brazilian contribution

The contribution of Brazilian scientists to research was fundamental. Of the 49 people from whom fossilized DNA was taken, seven skeletons dated 10,100 and 9,100 years ago came from Lapa to Santo, a rock shelter in Lagoa Santa.

Seven skeletons, along with dozens of others, were found and exhumed in subsequent archaeological campaigns on site, initially led by Walter Alves Neves, a physical anthropologist from IB-USP, and from 2011 by Strauss. Archaeological campaigns conducted by Neves in 2002-2008 were funded by the São Paulo Research Foundation – FAPESP.

In total, the new study examined fossil DNA from 49 people found at 15 archaeological sites in Argentina (two sites, 11 individuals dated for between 8900 and 6600 years ago), Belize (one place, three individuals dated between 9,400 and 7,300 years ago), Brazil (four websites, 15 people from 10-100 years ago and 1000 years ago), Chile (three sites, five people from 11,100 and 540 years ago) and Peru (seven pages, 15 people dated to 10,100 and 730 years ago).

Brazilian skeletons originate from the archaeological sites of Lapa do Santo (seven people dated around 9,600 years ago), Jabuticabeira II in the state of Santa Catarina (sambaqui or crustacean with five individuals dated around 2,000 years ago), and two river middens in the Ribeira Valley , state of São Paulo: Laranjal (two people dated around 6,700 years ago) and Moraes (one person around 5,800 years ago).

Paulo Antônio Dantas de Blasis, an archeologist associated with MAE-USP, conducted excavations in Jabuticabeira II, which was also supported by FAPESP as part of the Thematic Project.

The copies at the forest posts in São Paulo were directed by Levy Figuti, also an archaeologist at MAE-USP, and supported by FAPESP.

"Moraes' skeleton (5,800 years) and the Laranjal skeleton (6,700 years) are among the oldest in the south and southeast of Brazil," said Figuti. "These locations are strategically unique because they are located between the highlands of the Atlantic plateau and the coastal plain, contributing to a large extent to understanding how Southeast Brazil was populated."

These skeletons were found in 2000-2005. From the beginning, they presented a complex mixture of coastal and inland cultural features, and the results of their analysis generally differed, except for one skeleton diagnosed as Paleoindian (analysis of its DNA is not yet completed).

'The study just published is a major step forward in archaeological research, exponentially increasing the knowledge we only knew a few years ago about the archeology of people living in America,' said Figuti.

Hünemeier has recently made a significant contribution to the reconstruction of human history in South America using paleogenomics.

Indian genetics

Not all human remains found in some of the oldest archaeological sites in Central and South America belonged to the genetic descendants of the Clovis culture. Residents of several places did not have the DNA associated with Clovis.

"This shows that, apart from its genetic contribution, the second wave of migration to South America that was associated with Clovis could also bring with it technological principles that would be expressed at the famous fishtail points that are found in many parts of South America." Strauss said.

How many human migrations from Asia came to America at the end of the Ice Age over 16,000 years ago was unknown. The traditional theory, formulated in the eighties by Neves and other researchers, was that the first wave had African traits or features similar to those of the Australian Aborigines.

The well-known reconstruction of Luzia's face was carried out in accordance with this theory. Luzia is the name given to the skull of a fossil woman who lived in the region of Lagoa Santa 12 500 years ago and is sometimes referred to as the "first Brazilian."

Bust of Luzia with African features was built based on the morphology of the skull of British anatomical artist Richard Neave & # 39; and in the 1990s.

"However, the shape of the skull is not a reliable indicator of ancestors or geographical origin, and the basis for this type of inference is genetics" – explained Strauss.

"The genetic results of the new study show categorically that there was no significant relationship between the Lagoa Santa people and groups from Africa or Australia, so the hypothesis that the Luzia people are derived from the migration wave ahead of the ancestors of today's Indians has been questioned. that Luzia's people were completely Indian. "

The new bust replaced Luzia in the Brazilian scientific pantheon. Caroline Wilkinson, forensic anthropologist from Liverpool John Moores University in Great Britain and student Neave & # 39; produced a reconstruction of the face of one of the people exhumed in Lapa do Santo. The reconstruction was based on the retroduced digital skull model.

"The habit of the traditional facial reconstruction of Luzia with strong African features, this new facial reconstruction reflects much more accurately the physiognomy of the first inhabitants of Brazil, showing the generalized and indistinct features that have evolved great Indian diversity for thousands of years," Strauss said.

Study published in Cell– he added – also presents the first genetic data on the Brazilian coast samba.

"These monumental mounds were built around 2000 years ago by populations living on the coast of Brazil. The analysis of fossil DNA from funerals in the mines of Santa Catarina and São Paulo shows that these groups were genetically related to the Indians living today in the south of Brazil, especially the Kaingang groups." – He said.

According to Strauss, DNA extraction from fossils is technically very difficult, especially if the material was found in a tropical climate. For almost two decades, extreme fragmentation and significant pollution prevented various research groups from successfully extracting genetic material from bones found in Lagoa Santa.

This was done thanks to the methodological progress developed by the Max Planck Institute. As Strauss explained enthusiastically, much more remains to be discovered.

"Construction of the first archaeological laboratory in Brazil is due to begin in 2019, thanks to the partnership between the Museum of Archeology and Ethnology at the University of São Paulo (MAE) and its Institute of Bioscience (IB), funded by FAPESP, give new impetus to research on people in South America and Brazil, "Strauss said.

"To some extent, this study changes not only what we know about how the region was populated, but also significantly changes the way we study human skeletal remains," said Figuti.

Human remains were first found in Lagoa Santa in 1844, when Danish naturalist Peter Wilhelm Lund (1801-1880) discovered 30 deep skeletons in a flooded cave. Almost all these fossils are currently in the Museum of Natural History in Copenhagen. A single skull was left in Brazil. He was transferred by Lund to the Brazilian Institute of History and Geography in Rio de Janeiro.

Colonization at a dizzying pace

On the same day what Cell the article was published (November 8, 2018), an article in the journal Science they also reported new discoveries about fossil DNA from the first migrants to the Americas. André Strauss is one of the authors.

Of the 15 ancient skeletons from which genetic material was obtained, five belong to the Lund collection in Copenhagen. They come from 10,400 to 9,800 years ago. They are the oldest in the sample, and the Nevada person is 10,700 years old.

The sample contained fossilized human remains from Alaska, Canada, Brazil, Chile and Argentina. The results of the molecular analysis suggest that the population of the Americans by the first human groups from Alaska did not occur only by gradually occupying the territory as the population grew.

According to scientists responsible for the study, molecular data suggest that the first people who invaded Alaska or neighboring Yukon, divided into two groups. It happened between 17,500 and 14,600 years ago. One group colonized North and Central America, the other South America.

The people of the Americas arose abruptly when small teams of hunter-gatherers traveled far away and settled in new areas until they reached Tierra del Fuego in a movement lasting one or at most two thousand years.

Of the 15 people whose DNA was analyzed, it turned out that three of Lagoa Santa's five have genetic material from Australasia, as suggested by Neves's theory for the occupation of South America. Scientists are unable to explain the origin of this australian DNA or how it came to just a few people from Lagoa Santa.

"The fact that Australasia's genomic signature has been present for 10,400 years in Brazil, but is absent in all of the genomes researched so far that are so old or older and located further north, is a challenge considering its presence in Lagoa Santa, "they said.

Other fossils collected in the 20th century are the skull of Luzia, found in the 1970s. Almost 100 skulls dug by Neves and Strauss in the last 15 years are now in the USP. A similar number of fossils is found at the Pontifical Catholic University of Minas Gerais (PUC-MG).

But the vast majority of these osteological and archaeological treasures, probably more than 100 people, were deposited at the National Museum in Rio de Janeiro and probably destroyed during a fire that raged through this historic building on September 2, 2018.

The skull of Luzia was exhibited in the National Museum along with the reconstruction of the face of Neave & # 39; Scientists were afraid that they lost their fire, but fortunately it was one of the first objects excavated from the ruins. He crashed, but he survived. Fire destroyed the original reconstruction of the face (of which there are several copies).

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