Genetics: Study Traces the First Hawaiians Across Polynesia

A genetic method to look back in time

According to Archaeology magazine, which draws on information published by Science Alert, the researchers first used machine learning to isolate the DNA segments that reflect Polynesian ancestry. They then applied a method known as identity by descent, capable of detecting common ancestors.

This approach makes it possible to identify shared ancestors both among living people and among individuals who lived in the past. It thus offers a window onto generations that archaeology cannot reach directly, for lack of human remains or well-preserved settlement sites. It complements excavations carried out on Pacific islands rather than replacing them.

Migrations in small groups

The study shows that Polynesian populations moved across the Pacific in small numbers. This pattern may have caused genetic bottlenecks, meaning a reduction in genetic variation within a population. This phenomenon increases the likelihood that harmful mutations will spread, a process known as the founder effect.

The ancestors of Hawaiians would have experienced several of these bottlenecks during long voyages aboard double-hulled catamarans. These vessels, joined by a common structure, could carry people, food and plants over vast oceanic distances, but their capacity remained limited, which reinforced the dispersal of small, isolated groups.

Hawaii, an isolated northern archipelago

Hawaii is the only Polynesian island located in the Northern Hemisphere, which places it apart from the other lands of the Polynesian triangle. As Alexander Ioannidis explained, "Hawaii is the only Polynesian island in the Northern Hemisphere, so it's a long way from everything," a remark that underscores its geographic isolation.

For the researchers, this position partly explains the bottleneck effects observed in the archipelago's populations. The farther a settlement had to travel, the more the genetic diversity of the founding groups was likely to be reduced, with lasting consequences for later generations.

Unexpected links with Rapa Nui

The study suggests that Native Hawaiians are the closest genetic relatives of the people of Rapa Nui, Easter Island. The two islands are separated by more than 4,000 miles, and each lies about 2,000 miles from another island, which makes this link all the more surprising.

These two populations are also related to those of Mangareva, in the Gambier Islands of French Polynesia. According to Ioannidis, this island may have served as a starting point for the colonization of French Polynesia, a relay role within a navigation network that extended across the eastern Pacific.

What this research changes for the history of settlement

These findings complement archaeological and linguistic data on the settlement of the eastern Pacific Ocean, one of the last great expanses inhabited by humanity. They sketch a network of movements and inter-island links far more complex than a linear progression from east to west.

To explore the ancient history of Hawaii further, Archaeology magazine points to its report "Letter from Hawaii: Inside Kauai's Past," devoted to the past of the island of Kauai. Interested readers can also consult the collections of museums specializing in Oceanic cultures.