The history of America's human population is exactly right now. The largest and most comprehensive study ever conducted on the basis of fossil DNA derived from ancient human remains found on the continent has confirmed the existence of an ancestral population for all Indian ethnic groups, the past and the present.
More than 17,000 years ago, this original contingent crosses the Bering Point from Siberia to Alaska and began to exploit the New World. Fossil DNA shows the affinity between this migratory current and the population of Siberia and northern China. Contrary to traditional theory, she did not have a relationship with Africa or Australia.
The new study also reveals that the descendants of this migratory flow of ancestors were dispersed in two lines some 16,000 years ago, when they settled in North America.
Members of one line crossed Isthmus from Panama and crashed South America into three different successive waves.
The first wave was formed between 15,000 and 11,000 years. The second time happened 9,000 years ago. There are fossil DNA records of both migration across South America. The third wave is much more recent, but its impact is limited because it happened 4,200 years ago. Its members settled in the central Andes.
One study article was just published in the journal Cell a group of 72 researchers from eight countries affiliated with the University of Sao Paulo (USP) in Brazil, the Harvard University in the United States and the Mak Planck Institute for Human History in Germany, among others.
According to researchers' findings, the line that made the path between the northern and southern countries between 16,000 and 15,000 years belonged to the Clovis culture, which was named for a group of archaeological sites excavated in the western United States and dating from 13,500-11,000 years ago.
The Klovis culture was so named when the roof heads were found in the 1930s when swimming in Clovis, New Mexico. Clovis locations have been identified throughout the US and Mexico and Central America. In North America, people from Clovis fished Pleistocene megafauna like giant blanket and mammoth. With the decline of megafauna and its extinction 11,000 years ago, the Clovis culture disappeared. However, much earlier, hunter-hunters went south to explore new hunting grounds. They completed settling in Central America, proven by a 9,400-year-old human fossil DNA found in Belize and analyzed in a new study.
Later, perhaps during the expulsion of the mastodon herd, Clovis hunter-hunters cross Isthmus from Panama and spread to South America, as evidenced by genetic records from tombs in Brazil and Chile. This genetic proof is supported by well-known archaeological findings such as the Monte Verde site in southern Chile where people have been negotiating with mastodons 14,800 years ago.
Among the famous locations in Clovis, the only location for Clovis-related cemeteries is in Montana, where the remains of boys (Anzick-1) are found and date from 12,600 years. The DNA extracted from these bones has to do with DNA from a skeleton of people who lived between 10,000 and 9,000 years in caves near Lagoa Santa, Minas Gerais State, Brazil. In other words, the people of Lagoa Santa were partial descendants of migrants from Clovis from North America.
"From a genetic standpoint, people of Lagoa Santa are descendants of the first Americans," said archaeologist Andre Menezes Strauss, who coordinated the Brazilian part of the study. Strauss is affiliated with the Museum of Archeology and Ethnology at the University of Sao Paulo (MAE-USP).
"It is surprising that members of this first line of South Americans have not left identified descendants among today's Americans," he said. "Some 9,000 years ago, their DNA disappeared completely from fossil samples and replaced the DNA from the first migration wave, before Klovis's culture." All living Americans are the descendants of this first wave. "Lagoa Santa disappeared."
One of the possible reasons for the disappearance of DNA from the second migration is that it is diluted in the DNA of Americans who are descendants of the first wave and can not be identified by the existing methods of genetic analysis.
According to Tabita Hunemeier, a geneticist at the University of Sao Paulo Institute of Bioscience (IB-USP), "one of the main findings of the study was the identification of people of Lusia genetically related to the Clovis culture, which dismantled the idea of two biological components and the possibility that there were two migrations to America, one with African characteristics, and the other with Asian characteristics. "
"The Lusian people had to result from a migration wave originating in Beringia," she said, referring to the now submerged land bridge Bering that joined Siberia in Alaska during glaciation, when sea levels were lower.
"Molecular data suggest a population substitution in South America since 9,000 years ago, and Luzi's men have disappeared and have been replaced by Americans today, although both have a common origin in Beringia," Hunemeier said.
The contribution of a Brazilian researcher in the study was fundamental. Among the 49 people who have taken fossil DNA, seven skeletons date between 10,100 and 9,100 years, came from Lapa to Santo, a shelter for shelter in Lagoa Santa.
Seven skeletons, along with dozens of others, were found and exhumed in successive archaeological campaigns on the spot, which was initially led by Valter Alves Neves, a physical anthropologist at IB-USP, and since 2011 Strauss. Archaeological campaigns conducted by Neves between 2002 and 2008 were funded by the FAPESP Research Foundation in Sao Paulo.
In all, the new study examined a fossil DNA of 49 people found in 15 archaeological sites in Argentina (two sites, 11 people ranging between 8,900 and 6,600 years), Belize (one place, three people dating between 9,400 and 7,300 years) Brazil (four locations, 15 individuals dating between 10,100 and 1,000 years), Chile (three locations, five individuals dating between 11,100 and 540 years) and Peru (seven locations, 15 individuals date from 10,100 to 730 years).
Brazilian skeletons originate from the Lapa do Santo archaeological site (seven people from the date about 9,600 years ago), Jabuticabeira II in the state of Santa Catarina (sambakui or mussel midden from five individuals dated about 2,000 years ago), as well as from two rivers in the Ribeira valley , the state of Sao Paolo: Laranjal (two people date back about 6,700 years ago), and Moraes (one person gave about 5,800 years ago).
Paulo Antonio Dantas de Blasis, an archaeologist associated with the MAE-USP, led the digging on Jabuticabeir II, which also supported FAPESP through a thematic project.
Spear on the riverbanks in the state of Sao Paolo was led by Levi Figúte, also an archaeologist at the MAE-USP, and also supported by FAPESP.
"The Moraes skeleton (5,800 years old) and the Laranjal skeleton (about 6,700 years old) are among the oldest in the south and southeast of Brazil," Figuchi said. "These locations are strategically unique because they are between the plateau of the Atlantic Plateau and the coastal plains, significantly contributing to our understanding of how Southeast of Brazil was inhabited."
These skeletons were found between 2000 and 2005. From the very beginning they presented a complex mixture of coastal and internal cultural traits, and the results of their analysis usually vary, except in the case of one skeleton diagnosed as Paleoindian (the analysis of its DNA is not complete yet).
"The study just released is a major step forward in archaeological research, exponentially increasing what we knew until a few years ago about the archeogenetics of peasants of America," Figuchi said.
Hunemeier also recently made a significant contribution to the reconstruction of human history in South America using paleogenomics.
Not all of the human remains found on some of the oldest archaeological sites in Central and South America belonged to the genetic descendants of the Kloviska Culture. The residents of several locations did not have a DNA related to Clovis.
"This shows that, in addition to his genetic contribution, the second wave of migration to South America, which was linked to Clovis, could also bring technological principles that would be expressed in the well-known fissile spots in many parts of South America." Strauss said .
How many human migrations from Asia came to America at the end of the Ice Age more than 16,000 years ago have not been known so far. The traditional theory, which Neves and other researchers formulated in the 1980s, were that the first wave had African characteristics or properties similar to those of the Australian Aboriginal.
The well-known forensic reconstruction of the face of Luzia was carried out in accordance with this theory. Luzia is named after the fossil skull of a woman who lived in the region of Lagoa Santa before 12,500 years ago and is sometimes called "the first Brazilian".
Bozin Luzia with African characteristics was built on the basis of the morphology of the British anatomic artist Richard Neave's skull in the 1990s.
"However, the shape of the skull is not a reliable marker of ancestors or of geographical origin. Genetics is the best basis for this kind of conclusion," explains Strauss.
"The genetic results of the new study show categorically that there was no significant link between people Lagoa Santa and groups from Africa and Australia. So the hypothesis that people of Luzia originated from a migration wave before their ancestors of today's Americans was rejected. Luzin's people were completely American. "
The new bust replaced Luzia in a Brazilian scientific pantheon. Caroline Wilkinson, forensic anthropologist at Liverpool John Moores University in Great Britain and student Neave, reconstructed the face of one of the people exhumed in Lapa to Santo. Reconstruction is based on the retro-formulated digital skull model.
"He was used to the traditional educational reconstruction of Lusia with African characteristics, this new facial reconstruction reflects the physiognomy of the first inhabitants of Brazil more precisely, showing the generalized and unclear traits from which great Indian diversity has been established over thousands of years," said Strauss.
Study published in Cell, he added, is also the first genetic data on Brazilian coastal sambakuis.
"These monumental shells were built about 2,000 years ago from populations that lived on the coast of Brazil. The analysis of fossil DNA from wells in shells in Santa Catarina and Sao Paolo shows that these groups were genetically similar to Amerindians living in the south of Brazil, especially the group Kaingang, "he said.
According to Strauss, extraction of DNA from fossil is technically very challenging, especially if the material was found at a site with a tropical climate. For almost two decades, extreme fragmentation and significant contamination have prevented various research groups from successfully extracting bone genetics found in Lagoa Santa.
This is now done thanks to the methodological advances developed by Mak Planck Institute. As Strauss explained with enthusiasm, much remains to be revealed.
"The construction of the first archeo-genetic laboratory in Brazil will begin in 2019, thanks to a partnership between the Museum of Archeology and Ethnology at the University of Sao Paulo and the Institute of Bioscience (IB) with the funding of FAPESP, when it is ready, give a new move to explore the people of the South America and Brazil, "said Strauss.
"To some extent, this study not only changes what we know about how the area has been cut, but significantly changes are being made to the study of human remains of the bones," Figuti said.
Human remains were first found in Lagoa Santa in 1844, when the Danish naturalist Peter Vilhelm Lund (1801-1880) discovered about 30 skeletons deep in the flooded cave. Almost all of these fossils are now in the Copenhagen Natural History Museum of Denmark. One skull remained in Brazil. Lund donated to the Institute of History and Geography in Brazil, Rio de Janeiro.
Colonization by jumps and borders
On the same day as he did Cell the article was published (November 8, 2018), an article in the journal Science also reported new findings on fossil DNA from the first migrants to America. Andre Strauss is one of the authors.
Among the 15 ancient skeletons from which genetic material is taken, the five belong to the Lund collection in Copenhagen. They date between 10,400 and 9,800 years. They are the oldest in the sample, along with a person from Nevada estimated at 10,700 years.
The sample consisted of fossilized human remains from Alaska, Canada, Brazil, Chile, and Argentina. The results of his molecular analysis suggest that people from America came from the first human groups outside of Alaska only through the gradual occupation of the territory at the same time as population growth.
According to researchers responsible for the study, molecular data suggests that the first people who attacked Alaska or neighboring Iukon were divided into two groups. It happened between 17,500 and 14,600 years. One group colonized North and Central America, the other South America.
The backbones of America were passing by jumps and borders, as small groups of hunters and collectors went far and wide to settle in new areas until they arrived in Tierra del Fuego in a move that lasts for a maximum of two thousand years.
Among the 15 DNA analyzed, three of the Lagoa Santa Five were discovered to have some genetic material from Australia, suggested in a theory proposed by Neves for the occupation of South America. The researchers are unable to explain the origin of this Australian DNA or how it ended up in just a few people, Lagoa Santa.
"The fact that the genomic signature of Australia was present for 10,400 years in Brazil, but is absent in all tested genes to date, who are older or older and found further in the north, is a challenge given his presence in Lagoa Santa," they said.
Other fossils collected during the twentieth century included the Luzia lobby, found in the 1970s. Almost 100 skulls that Neves and Strauss had dug up for the past 15 years have now been held in the USP. A similar number of fossils is held at the Pontifical Catholic University Minas Gerais (PUC-MG).
But the vast majority of these osteological and archaeological resources, belonging perhaps to more than 100 individuals, were deposited at the National Museum in Rio de Janeiro and were probably destroyed in a fire that went through this historic building on September 2, 2018.
The skull was exposed in the National Museum with the reconstruction of Nave's face. The scientists feared it was lost in the fire, but luckily it was one of the first items recovered from the ruins. He broke up, but survived. The fire destroyed the original reconstruction of the face (of which there are several copies).