Nature, in what was almost certainly not an April Fools’ gag, reports that there’s genetic evidence, now, that Polynesians traveled to the Amazon in days gone by – because old Brazilians share DNA with South Pacific islanders:
Indigenous people that lived in southeastern Brazil in the late 1800s shared some genetic sequences with Polynesians, an analysis of their remains shows. The finding offers some support for the possibility that Pacific islanders traded with South America thousands of years ago, but researchers say that the distinctive DNA sequences, or haplogroups, may have entered the genomes of the native Brazilians through the slave trade during the nineteenth century.
…
[Sérgio Pena, a molecular geneticist at the Federal University of Minas Gerais in Belo Horizonte, Brazil,] and his colleagues studied short stretches of mitochondrial DNA (mtDNA) in samples drilled from teeth in 14 Botocudo skulls kept in a museum collection in Rio de Janeiro. By analysing material from inside the teeth, the team minimized the possibility of contamination with DNA from the numerous people who have probably handled the skulls….
But mtDNA from two of the skulls included a haplogroup commonly found in Polynesia, Easter Island and other Pacific island archipelagos, the researchers report today in Proceedings of the National Academy of Sciences.
…
The researchers say that it is possible — but unlikely — that the DNA could have come from Polynesians who voyaged from remote islands to the western coast of South America. Those traders or their progeny would then have made their way to southeastern Brazil and settled or interbred with natives. But that, too, is improbable, says Pena, because the Andes are a formidable barrier that west coast residents typically did not climb or cross. Although researchers have suggested that ancestors of some species of chickens made their way to Chile through trade with pre-Columbian seafarers from Polynesia, a subsequent study poked holes in that conclusion.
They say it’s likelier that the DNA came from slaves who were brought to Brazil from Madagascar. But they’re not able to dismiss any other explanation yet.