Genetic study reveals how ancient seafarers settled vast Polynesia

Beginning more than a millennium ago, intrepid seafarers traversed vast Pacific Ocean expanses in doublehulled sailing canoes to reach the farflung islands of Polynesia, the planet's last habitable region to be settled by people.

A genetic study published on Wednesday has deciphered the timing and sequence of this settlement of an area spanning about a third of Earth's surface, with Samoa as the starting point while Rapa Nui, also called Easter Island, and other locales known for megalithic statues were among the last to be reached.

"Many of the distances were immense," said Stanford University computational geneticist Alexander Ioannidis, lead author of the research appearing in the journal Nature.

For example, the study found that Rapa Nui was settled in about 1210 AD after an open-sea voyage covering roughly 1,600 miles (2,575 km). Historians believe that family groups of perhaps 30 to 200 people sailed at a time aboard double-hulled canoes that operated similarly to modern catamarans and used a lateen, or triangular, sail.

Genomic data from 430 modernday people from 21 Pacific island populations helped unravel Polynesia's genetic history.

"Each living individual retains a genetic record of all the ancestors from whom they inherited their DNA, so by analyzing together hundreds of individuals we can create a genomic network where connections, splitting patterns and dates can be inferred," said geneticist and study co-author Andres Moreno-Estrada of Mexico's CINVESTAV network of research centers.