Polynesian mtDNA in C19 Brazilian Amerindians

DNA study links indigenous Brazilians to Polynesians

One broad group of these Palaeoamericans — the Botocudo people, who lived in inland regions of southeastern Brazil — stands out, having skull shapes that were intermediate between those of other Palaeoamericans and a presumed ancestral population in eastern Asia.

Now, a genetic analysis sheds light on the possible heritage of the Botocudo. Pena 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 since they arrived at the museum in the late 1800s.

The mtDNA from 12 of the skulls matched a well-known Palaeoamerican haplogroup. 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 Sciences1. A separate lab confirmed the result with samples from one of the skulls, indicating that the ‘Polynesian haplogroup’ did not result from contamination, the researchers contend.

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. [. . .]

The researchers also entertain scenarios in which the haplogroup arrived in South America via the slave trade. Around 2,000 Polynesians were brought to Peru in the 1860s, and some could have ended up in Brazil, although the researchers say that they are not aware of any evidence that this occurred. And between 1817 and 1843, approximately 120,000 slaves were shipped from Madagascar to Brazil — and some of them were probably transported to areas where the Botocudo also lived. Although the researchers consider the latter scenario to be the most probable, Pena says: “We currently don’t have enough evidence to definitively reject any of these scenarios.”

“This is a pretty exciting initial result,” says Alice Storey, an archaeologist at the University of New England in Armidale, Australia. Further studies of genetic material from the skulls, including detailed analyses of nuclear DNA (which contains much longer genetic sequences than mtDNA), could offer more insight into the mysterious ancestry of the Botocudo, she says.

The paper: Identification of Polynesian mtDNA haplogroups in remains of Botocudo Amerindians from Brazil