Polynesians and Native Americans paired up around 800 years ago, creating a genetic signature that is still found today, according to a new study.
The Stanford University study used genetic data from 800 indigenous people living in several South American countries, Mexico and Polynesia.
It is the first study to show, through conclusive genetic analyses, that the two groups met each other before Europeans arrived in South America.
"We found identical-by-descent segments of Native American ancestry across several Polynesian islands. It was conclusive evidence that there was a single shared contact event," lead researcher Alexander Ioannidis said.
"I think this work helps piece together those untold stories - and the fact that it can be brought to light through genetics is very exciting to me,"
"It's really exciting that we, as data scientists and geneticists, are able to contribute in a meaningful way to our understanding of human history."
One thing that the research doesn't show is where exactly the two populations met.
Native American people could have travelled to Polynesia or Polynesians could have travelled to the region now known as Colombia before returning to Polynesia.
Before the study, scientists reasoned that common cultural elements, such as a similar word for sweet potato, showed that the populations could have mingled before Europeans arrived in South America.
"The sweet potato is native to the Americas, yet it's also found on islands thousands of miles away," Ioannidis said.
"On top of that, the word for sweet potato in Polynesian languages appears to be related to the word used in Indigenous American languages in the Andes."
Other studies, that have analysed ancient DNA from bones belonging to Native Americans and native Polynesians were unable to provide sufficient evidence of a link between the two populations.
