Polynesian DNA found in ancient Native American bones
Molecular geneticist Sergio Pena at the Federal University of Minas Gerais in Brazil and his colleagues analyzed DNA from the Botocudo, who dwelt in what is now southeastern Brazil. They lived a nomadic, hunter-gatherer lifestyle, wore ornaments in their lips and ears Portuguese colonizers dubbed “botoques,” and were virtually entirely wiped out by the end of the 19th century during a war Portugal declared on all Native American tribes that did not accept European laws.
The researchers extracted DNA and partially sequenced the mitochondrial DNA from teeth obtained from 14 Botocudo skulls housed at the Federal University of Rio de Janeiro. Bewilderingly, in two of the skulls, they discovered mitochondrial lineages typically considered Polynesian.
“Everything was both surprising and exciting from the very start,” Pena says. “The first thought that came to my mind was that we had the rule out the possibility of some contamination, although it would be difficult exactly of that kind, since there were no Polynesian individuals in the chain of custody.” Another lab ultimately independently confirmed these findings.
The most exciting potential explanation of the DNA findings is that ancestors of the Botocudo once interbred with those of Polynesians before the peopling of the Americas 15,000 to 20,000 years ago, Pena says. Prior studies of skull shapes hinted that two distinct groups entered the Americas—one more Asian type seen now in the vast majority of extant Native Americans, and an earlier type seen in skeletons in Brazil and elsewhere that resembled some African groups, Australians, Melanesians, and Polynesians such as Easter Islanders.
“Unfortunately, there are several lines of evidence that render this hypothesis very tenuous,” Pena says. Mainly, the sequences that seem Polynesian in the Botocudo DNA appear too recent—they lack mutations one would expect would have accumulated over time if the sequences had been introduced before the peopling of the Americas. Such mutations were not seen in the portions of DNA the researchers studied, although they do not rule out the possibility such mutations exist in DNA they have not analyzed yet.
Another imaginable pre-Columbian scenario involves more recent direct contact between Polynesians and South Americans before Europeans arrived. For instance, Polynesian chicken bones have been found in Chile, and pre-Columbian signs of sweet potato and bottle gourd, both typical of South America, have been found on Easter Island. Still, despite those findings, Pena and his colleagues find the idea of such Polynesian descendants crossing the Andes to end up in Brazil too unlikely to seriously entertain.
“We would caution the lay public not to use our data to jump to the conclusion that trans-Pacific migrations occurred from Polynesia to the Americas,” Pena says.
Two more potential explanations are rooted after the arrival of Europeans. One involves the “blackbirding trade” that kidnapped or tricked people into work as laborers in the 1860s brought about 2,000 Polynesians to Peru. However, as far as the researchers can tell, there is no evidence any of these Peruvian slaves were transported to Brazil.
In addition, between 1817 and 1843, the African slave trade brought about 120,000 slaves from the Madagascar region to Brazil to work close to Botocudo areas. In these regions, the Native Americans were drafted to work side-by-side with African slaves in plantations and may have interbred. Female slaves from Madagascar may also have been kidnapped by Botocudos or ran away and found refuge among them. In fact, the kidnapping of a female by Botocudos is a central theme of an 1870 Brazilian opera, “Il Guarany.”
“We do not believe that these scenarios encompass all the possibilities and we are keeping our mind open that a fifth or sixth scenario may still appear,” Pena says.