Autor Tópico: Evidências de colonização por povos asiáticos nas Américas  (Lida 893 vezes)

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Offline EuSouOqueSou

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Evidências de colonização por povos asiáticos nas Américas
« Online: 07 de Abril de 2013, 20:04:47 »
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Even the scientists who discovered it aren't sure how it got there.

The Polynesians' epic voyages of exploration and colonization across the Pacific are one of humanity's most impressive accomplishments (even if the local bird life wasn't likely to have enjoyed it). Having most probably started in Taiwan, the explorers reached and settled on islands across most of the Pacific, as far north as Hawaii and as far south as New Zealand. And recent evidence shows that they also stopped in South America, where they stayed long enough to pick up food crops that eventually wound up distributed across the Pacific as well.

By the time they reached South America, however, several large and sophisticated civilizations had already developed along the west coast of that continent. This is in sharp contrast to the uninhabited islands that the Polynesians were used to colonizing, which raises questions about whether any of the voyagers were likely to have stayed in the newly discovered land. Genetic surveys of native populations in Peru and elsewhere have indicated that, if any did stick around, they didn't make a significant contribution to the local gene pool.

But now, some researchers have found some Polynesian DNA in the remains of some Native Americans. Oddly, however, the remains are on the exact opposite side of the continent from where the Polynesians are likely to have landed. Even the researchers themselves are at a bit of a loss to explain it; after considering several possible causes, even the one they find most likely gets labelled as "fanciful."

Although the interpretation is bewildering, the data is pretty clear-cut. The authors focused on a tribe that originally lived in the south-east of Brazil called the Botocudo. This group was violent and independent, and didn't come under the control of the Portuguese colonial power. In 1808, the authorities essentially declared war against any group that fit this description. By the end of that century, the Botocudo had essentially ceased to exist as a distinctive ethnic group.

The remains of several Botocudo individuals, however, were preserved in museums, and the authors obtained DNA from over a dozen of them. That DNA was used to study parts of the mitochondrial genome, which is inherited exclusively through female lineages. Because it's relatively easy to obtain and sequence, mitochondrial DNA has been used for a variety of studies of human evolution, and there's a wealth of data available on the variations associated with different populations.

A dozen of these samples produced the sorts of sequences you'd typically see in Native American populations. But two others have a set of distinctive changes that, to date, have only been found in populations associated with Polynesian cultures.

So, how to explain this? The authors consider a number of possibilities. One is based on the fact that both Polynesians and Native Americans are originally derived from Asian populations. Thus, it's possible that the ancestors of both these people shared a variant that has either gone extinct on the Asian mainland, or has just escaped the reach of our current sequencing efforts. However, all indications are that some of the changes we associate with Polynesians appear to be recent, and likely occurred after the population was on Taiwan. So, the authors consider that prospect unlikely.

The next possibility they consider is that the DNA arrived with the Polynesian voyagers themselves, which might seem plausible except for the fact that there's an entire continent's worth of individuals in between who, to date, seem to have no hint of Polynesian DNA. Plus some forbidding geography. "There still would remain the need to explain how these migrants crossed the Andes and ended up in Minas Gerais, Brazil," the authors muse. "We feel that such a scenario is too unlikely to be seriously entertained."

So, what's left? The best of a bad bunch of explanations. Towards the end of the African slave trade, Britain's ban on slavery led it to interdict vessels along the west coast of Africa. That shifted some of the trade to elsewhere, including Madagascar. That island was also settled by Polynesians, and about 20 percent of its population appears to carry DNA variants consistent with the Brazilian find. Once brought to Brazil, there were a few decades in which these individuals could have been kidnapped by and assimilated into the Botocudo (possibly producing offspring) before the tribe was exterminated. The authors helpfully note that a kidnapping of this sort was the subject of an 1870 opera by a Brazilian composer.

The timing and number of coincidences needed are what cause the authors to term this "fanciful." Still, they consider this the best of a bad lot of explanations.

The paper's somewhat odd, in that the authors couch their introduction in terms of debates about the peopling of North America prior to the arrival of Europeans, all of which are somewhat aside from the point. Instead, they've stumbled across a real scientific mystery, one that is likely to be very challenging to sort out. And, like many other historical accidents, this one may perpetually defy easy explanations.

PNAS, 2013. DOI: 10.1073/pnas.1217905110  (About DOIs).

http://arstechnica.com/science/2013/04/polynesian-dna-mysteriously-shows-up-in-a-brazilian-tribe/
« Última modificação: 19 de Março de 2018, 15:26:37 por Geotecton »
Qualquer sistema de pensamento pode ser racional, pois basta que as suas conclusões não contrariem as suas premissas.

Mas isto não significa que este sistema de pensamento tenha correspondência com a realidade objetiva, sendo este o motivo pelo qual o conhecimento científico ser reconhecido como a única forma do homem estudar, explicar e compreender a Natureza.

Offline Buckaroo Banzai

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Re:Polynesian DNA mysteriously shows up in a Brazilian tribe
« Resposta #1 Online: 07 de Abril de 2013, 21:02:00 »
Será que isso de alguma forma pode se encaixar com aquelas evidências (supostamente) de colonizações anteriores à dos nativo-americanos "atuais"? Já vi defenderem que nativos de Tierra del Fuego tem características físicas e genéticas compatíveis com isso, e vestígios/ossos na América do Sul e do Norte também mostram habitanes com uma morfologia um pouco diferente, mais próximos a nativos australianos, que talvez tenham também esses alelos em comum...

Um desses vestígios sulamericanos é a brasileria "Luzia".

Offline Gigaview

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Re:Polynesian DNA mysteriously shows up in a Brazilian tribe
« Resposta #2 Online: 07 de Abril de 2013, 23:31:45 »
Existe ainda a possibilidade dos nativos americanos terem chegado à Polinésia, conforme se tentou demonstrar com a Expedição Kon-tiki em 1947.
Não passei no teste da MENSA mas completei o 2o. Grau.

Offline Gigaview

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Re:Polynesian DNA mysteriously shows up in a Brazilian tribe
« Resposta #3 Online: 07 de Abril de 2013, 23:36:03 »
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Recently dug chicken bones on the coast of Chile have been dated before Columbus' "discovery" of America and their DNA matched fowls breeds of Polynesia.
http://news.softpedia.com/news/Chicken-Proves-it-Polynesians-Entered-America-Before-Columbus-56435.shtml

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Between 300 and 1200 CE, Polynesians in canoes spread throughout the Polynesian Triangle going as far as Easter Island, New Zealand and Hawaii, and perhaps on to the Americas. The sweet potato, which is native to the Americas, was widespread in Polynesia when Europeans first reached the Pacific. Sweet potato has been radiocarbon-dated in the Cook Islands to 1000 CE, and current thinking is that it was brought to central Polynesia c. 700 CE and spread across Polynesia from there.[5] It has been suggested[6] that it was brought by Polynesians who had traveled to South America and back, or that South Americans brought it to the Pacific. It is unlikely that the plant could successfully float across the ocean by natural means.[7]

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Furthermore, in December 2007, several human skulls with Polynesian features, such as a pentagonal shape when viewed from behind, were found lying on a shelf in a museum in Concepción. These skulls turned out to be originating from Mocha Island, an island just off the coast of Chile in the Pacific Ocean, nowadays inhabited by Mapuche. Professor Lisa Matisoo-Smith of the University of Otago and José Miguel Ramírez Aliaga of the University of Valparaíso hope to win agreement soon with the locals of Mocha Island to begin an excavation search for Polynesian remains on the island.[12]

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Dutch linguists and specialists in Amerindian languages Willem Adelaar and Pieter Muysken have suggested that two lexical items may be shared by Polynesian languages and language of South America. One is the name of the sweet potato, which was domesticated in the New World. Easter Island kumara and Hawaiian ʻuala (also compare the Māori name kumāra) may be connected with Quechua and Aymara k’umar ~ k’umara. A possible second is the word for 'stone axe', Easter Island toki, Mapuche toki, and further afield, Yurumangui totoki 'axe'. According to Adelaar and Muysken the similarity in the word for sweet potato, "constitutes near proof of incidental contact between inhabitants of the Andean region and the South Pacific", though according to Adelaar and Muysken the word for axe is not as convincing. The authors argue that the presence of the word for sweet potato suggests sporadic contact between Polynesia and South America, but no migrations.[15]
http://en.wikipedia.org/wiki/Pre-Columbian_trans-oceanic_contact
« Última modificação: 07 de Abril de 2013, 23:43:02 por Gigaview »
Não passei no teste da MENSA mas completei o 2o. Grau.

Offline Buckaroo Banzai

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Re:Polynesian DNA mysteriously shows up in a Brazilian tribe
« Resposta #4 Online: 08 de Abril de 2013, 14:43:48 »
Existe ainda a possibilidade dos nativos americanos terem chegado à Polinésia, conforme se tentou demonstrar com a Expedição Kon-tiki em 1947.

Acho muito improvável, pois pelo lado de genética, o que se esperaria dessa ocorrência seria o padrão contrário, acharem alelos de ameríndios misteriosamente na Polinésia. Poderia ainda funcionar, mas o alelo originalmente ameríndio teria que praticamente desaparecer nas Américas e se tornar extremamente comum na Polinésia, o que é muito menos provável do que um alelo já comum na Polinésia ir parar nas Américas e se manter raro por lá.

Mas quem sabe? Foram poucos achados por enquanto, talvez se derem uma olhada melhor nos genes de pessoas e outros eventuais vestígios, encontrassem mais desses alelos, aumentando as chances disso.


Offline EuSouOqueSou

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Re:Polynesian DNA mysteriously shows up in a Brazilian tribe
« Resposta #6 Online: 26 de Abril de 2013, 02:04:41 »
Dá pra traduzir? :P
Qualquer sistema de pensamento pode ser racional, pois basta que as suas conclusões não contrariem as suas premissas.

Mas isto não significa que este sistema de pensamento tenha correspondência com a realidade objetiva, sendo este o motivo pelo qual o conhecimento científico ser reconhecido como a única forma do homem estudar, explicar e compreender a Natureza.

Offline EuSouOqueSou

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Re:Polynesian DNA mysteriously shows up in a Brazilian tribe
« Resposta #7 Online: 19 de Março de 2018, 11:18:25 »
Mais evidências de colonização por povos asiáticos nas Américas:

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...e ameríndia (20,3%), esta com ascendência de povos asiáticos - resultado que, de acordo com o professor de Medicina da UFC e integrante do estudo, Alexandre Havt, foi "a maior surpresa". "Poucas pesquisas investigam a origem dos nossos índios, e essa verificou que os genes indígenas dos nordestinos têm origem do povo Bangladesh, na Ásia. Todos sabem que o asiático chegou à América, mas não tínhamos ideia de que tipo de população ele formou", aponta. A análise das raízes do sangue que corre no Nordeste foi realizada a partir da saliva de 1.538 crianças de até 3 anos nas cidades de Crato, no Ceará; Picos, no Piauí; Ouricuri, em Pernambuco; e Cajazeiras, Sousa e Patos, na Paraíba.


http://diariodonordeste.verdesmares.com.br/cadernos/cidade/nordestino-tem-mais-sangue-europeu-do-que-indigena-1.1909852

P.S.: moderação, favor mudar o título do tópico para "Evidências de colonização por povos asiáticos nas Américas"
Qualquer sistema de pensamento pode ser racional, pois basta que as suas conclusões não contrariem as suas premissas.

Mas isto não significa que este sistema de pensamento tenha correspondência com a realidade objetiva, sendo este o motivo pelo qual o conhecimento científico ser reconhecido como a única forma do homem estudar, explicar e compreender a Natureza.

Offline André Luiz

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Re:Evidências de colonização por povos asiáticos nas Américas
« Resposta #8 Online: 19 de Março de 2018, 22:41:39 »
 Isso sempre não foi óbvio?

Todo indiozinho tem cara de japa

 

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