Having recently revisited Thor Heyerdahl’s Kon-Tiki voyage and his theory of peoples from Peru reaching Polynesia about 1,500 years ago, this paper about a possible (when?) migration (or excursion) from Polynesia to Brazil was a timely reminder that very rarely will we be able to “prove” things that happened in the time before recorded history. Mitochondrial sequences belonging to haplogroups characteristic of Polynesians was found in DNA extracted from ancient skulls of the now extinct Botocudo Indians from Brazil.
Identification of Polynesian mtDNA haplogroups in remains of Botocudo Amerindians from Brazil, Vanessa Faria Gonçalves et al, PNAS, 2013. DOI: 10.1073/pnas.1217905110
There is a consensus that modern humans arrived in the Americas 15,000–20,000 y ago during the Late Pleistocene, most probably from northeast Asia through Beringia. However, there is still debate about the time of entry and number of migratory waves, including apparent inconsistencies between genetic and morphological data on Paleoamericans. Here we report the identification of mitochondrial sequences belonging to haplogroups characteristic of Polynesians in DNA extracted from ancient skulls of the now extinct Botocudo Indians from Brazil. The identification of these two Polynesian haplogroups was confirmed in independent replications in Brazil and Denmark, ensuring reliability of the data. Parallel analysis of 12 other Botocudo individuals yielded only the well-known Amerindian mtDNA haplogroup C1. Potential scenarios to try to help understand these results are presented and discussed. The findings of this study may be relevant for the understanding of the pre-Columbian and/or post-Columbian peopling of the Americas.
Apr 5 2013, 9:15pm WEDT
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. ……