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Category Archives: Brazil

OSL dating: Brazilian site is 22,000 years ago

Toca da Tira Peia is the new name of American prehistory, providing an OSL date for the layer of scattered stone tools of c. 22,000 years BP. Located near the also controversial Pedra Furada site, the date seems to give some support to those who dare to think outside the box on the early peopling of America.
Christelle Lahaye et al., Human occupation in South America by 20,000 BC: the Toca da Tira Peia site, Piauí, Brazil. Science 2013. Pay per view LINK [doi:10.1016/j.jas.2013.02.019]

Abstract


When and how did the first human beings settle in the American continent? Numerous data, from archaeological researches as well as from palaeogenetics, anthropological and environmental studies, have led to partially contradictory interpretations in recent years, often because of the lack of a reliable chronological framework. The present study contributes to the establishment of such a framework using luminescence techniques to date a Brazilian archaeological site, the Toca da Tira Peia. It constitutes an exemplary case study: all our observations and measurements tend to prove the good integrity of the site and the anthropological nature of the artifacts and we are confident in the accuracy of the luminescence dating results. All these points underline the importance of the Toca da Tira Peia. The results bring new pieces of evidence of a human presence in the north-east of Brazil as early as 20,000 BC. The Toca da Tira Peia thus contributes to the rewriting of the history of the peopling of the American continent.

There are slightly older sites in North America, however they are all surrounded into some degree of controversy: Topper in South Carolina is dated to c. 23,000 cal-BP (C14) while some sites in Alberta, located in the Mackenzie “ice-free corridor” have also dates under the LGM layer (i.e. > 21 Ka BP).
There’s actually nothing impossible about such early dates in my understanding.

See also:

 

Alert: Brazilian mining project to destroy dozens of archaeological sites in the Amazon

At least 24 caves, which hold major archaeological relevance for the understanding of the early inhabitation of the Amazon basin, will be destroyed by a gigantic iron mine project in the region of Carajás (Pará, Brazil). 
While the area is a national forest and the Brazilian law demands in principle that archaeological sites be preserved, the government has given Vale, the Brazilian mining giant, what amounts to a blank license for the destruction of whatever stands in their way.
Not just that, but Vale holds control over what ongoing research can disclose of the importance of the caves:
Renato Kipnis, a respected archaeologist in São Paulo whom Vale hired to
survey the caves of Carajás, said that Vale had prohibited him from
discussing their archaeological significance, because of a
confidentiality agreement Vale had required him to sign. Later, a Vale
spokeswoman allowed Mr. Kipnis to be interviewed by e-mail, but only if
the company was allowed to vet his replies. 

In written replies screened by Vale, he marveled at the importance of the caves. 
Source: New York Times
NASA image of the already existing Carajás mine
 
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Posted by on December 19, 2012 in America, archaeology, Brazil, Latin America, Native Americans

 

The Xavantes as genuine unmixed Native Americans

Xavantes (cc Agência Brasil)
A new paper proclaims that Xavantes appear to be one of the less mixed and or more genetically distinctive Native American people of present day.
Patricia C. Kuhn et al., Genome-Wide Analysis in Brazilian Xavante Indians Reveals Low Degree of Admixture. PLoS ONE 2012. Open access ··> LINK [doi: 10.1371/journal.pone.0042702]

Abstract

Characterization of population genetic variation and structure can be used as tools for research in human genetics and population isolates are of great interest. The aim of the present study was to characterize the genetic structure of Xavante Indians and compare it with other populations. The Xavante, an indigenous population living in Brazilian Central Plateau, is one of the largest native groups in Brazil. A subset of 53 unrelated subjects was selected from the initial sample of 300 Xavante Indians. Using 86,197 markers, Xavante were compared with all populations of HapMap Phase III and HGDP-CEPH projects and with a Southeast Brazilian population sample to establish its population structure. Principal Components Analysis showed that the Xavante Indians are concentrated in the Amerindian axis near other populations of known Amerindian ancestry such as Karitiana, Pima, Surui and Maya and a low degree of genetic admixture was observed. This is consistent with the historical records of bottlenecks experience and cultural isolation. By calculating pair-wise Fst statistics we characterized the genetic differentiation between Xavante Indians and representative populations of the HapMap and from HGDP-CEPH project. We found that the genetic differentiation between Xavante Indians and populations of Ameridian, Asian, European, and African ancestry increased progressively. Our results indicate that the Xavante is a population that remained genetically isolated over the past decades and can offer advantages for genome-wide mapping studies of inherited disorders.

The Xavantes, comprising today some 10,000 people, have suffered repeated hostility from the Western civilization in Brazil since centuries ago. In spite of all they have managed to remain proud and distinct.

Fig. 2 three-dimensional global PCA with emphasis in American populations

Fig. 3 (edited by me: only the labeling): neighbor-joining global tree

 

Brazilians are much more homogeneous than ‘racial’ categories suggest

This is a very revealing paper on Brazilian genetic makeup and the shallowness of racial classification in general:
Abstract
Based on pre-DNA racial/color methodology, clinical and pharmacological trials have traditionally considered the different geographical regions of Brazil as being very heterogeneous. We wished to ascertain how such diversity of regional color categories correlated with ancestry. Using a panel of 40 validated ancestry-informative insertion-deletion DNA polymorphisms we estimated individually the European, African and Amerindian ancestry components of 934 self-categorized White, Brown or Black Brazilians from the four most populous regions of the Country. We unraveled great ancestral diversity between and within the different regions. Especially, color categories in the northern part of Brazil diverged significantly in their ancestry proportions from their counterparts in the southern part of the Country, indicating that diverse regional semantics were being used in the self-classification as White, Brown or Black. To circumvent these regional subjective differences in color perception, we estimated the general ancestry proportions of each of the four regions in a form independent of color considerations. For that, we multiplied the proportions of a given ancestry in a given color category by the official census information about the proportion of that color category in the specific region, to arrive at a “total ancestry” estimate. Once such a calculation was performed, there emerged a much higher level of uniformity than previously expected. In all regions studied, the European ancestry was predominant, with proportions ranging from 60.6% in the Northeast to 77.7% in the South. We propose that the immigration of six million Europeans to Brazil in the 19th and 20th centuries – a phenomenon described and intended as the “whitening of Brazil” – is in large part responsible for dissipating previous ancestry dissimilarities that reflected region-specific population histories. These findings, of both clinical and sociological importance for Brazil, should also be relevant to other countries with ancestrally admixed populations.

Real ancestry of various regional populations divided by racial self-description (fig. 2):

It is I think quite interesting to realize that racial categories are often meaningless in representing the real ancestry of individuals collectives. This is specially true for the brown (pardo) and black (preto)  categories but, in the north specially, it is also very true for the category white (branco). In this sense, the Brazilian census would probably do well dropping racial categories altogether, as they are obviously without meaning. 
Overall Brazilians seem mostly of European ancestry (60-80%), with some lesser regional variability, as is very apparent in figure 3:

Native American ancestry is rather homogeneous by regions, making up 7-10% of the ancestry except in the North (Amazon) region, where it’s double (19%). African ancestry is somewhat more important and also regionally variable: 10% to 29% (this last in the Northeast).
Notice anyhow that the samples were collected in six specific cities and that specially the vast Amazon region is probably under-represented (as the only sample comes from Belem, a large city of the coast). I’d dare say that the vast Brazilian interior (all samples are from the coast) must be stronger in Native American ancestry, even if we do not consider the surviving aboriginal populations, but only the creoles.