New genetic research shows that there was mingling between ancient Indigenous peoples from Polynesia and South America, revealing a single episode of interbreeding roughly 800 years ago after an epic transoceanic journey.

The question of such contact — which was long hypothesized, in part based on the enduring presence in Polynesia of a staple food in the form of the sweet potato that originated in South and Central America — had been keenly debated among scientists.

People from four island sites in French Polynesia — Mangareva and the Pallisers in the Tuamotu Archipelago and Fatu Hiva and Nuku Hiva in the Marquesas Islands — bore DNA indicative of interbreeding with South Americans most closely related to present-day Indigenous Colombians around 1200 AD.

These islands are roughly 6,800 kilometres from South America.

People from Chile's Rapa Nui, or Easter Island, also had South American ancestry, some from modern Chilean immigrants and some from the same ancient intermingling as the other islands.

Rapa Nui, located 3,700 kilometres west of South America and known for its massive stone figures (called moai), was settled some time after the interbreeding 800 years ago.