Native Hawaiians have the closest genetic ties to people from Rapa Nui, according to a study published in Science. Alexander Ioannidis, a genetics and biomedical data science researcher at Stanford University and co-senior author, said the work uncovers where the native people of Hawaii had come from.
The researchers used previously published whole-genome sequencing data from 1,050 individuals across French Polynesia, 12 unpublished genomes from Rapa Nui, and genomic data from Native Hawaiians, Samoans, and Tongans from the NIH's All of Us Biobank. They also used the Gnomix analyzer to isolate genetic segments of Polynesian ancestry and an identity by descent method to reveal common ancestors.
Hawaii and Rapa Nui
Ioannidis said, "What we uncover in this paper is where the native people of Hawaii had come from" and added, "Hawaii is the only Polynesian island in the Northern Hemisphere, so it's a long way from everything." The distance between Hawaii and Rapa Nui is about 7,000 kilometers, while each is more than 3,000 kilometers from the nearest inhabited island.
The study places Mangareva Island as a likely ancestral launching point because it was less related to people from Hawaii and Rapa Nui than those two populations were to each other. That leaves the closest genetic link at the far end of the route, even as Mangareva Island sits in the middle of the reconstruction.
Polynesian migration history
The researchers said Native Hawaiians may have experienced repeated genetic bottlenecks as small groups traveled between islands on double-hulled catamarans that could only accommodate dozens of people. In that setting, each migration could narrow the gene pool and make later populations more closely related than the route itself would suggest.
They also placed the Hawaii finding inside a broader migration sequence they had previously described, from Samoa to Fiji and Tonga, then eastward toward the Cook Islands, then the Society Islands including Tahiti. This study extends that genetic reconstruction into Hawaii and Rapa Nui, using the same kind of genome-wide comparison to connect islands without written chronicles.
For Native Hawaiians, the paper’s key result is that the strongest genetic signal points to Rapa Nui, not to the island named as the likely launch point. The open question is how much of the bottleneck effect came from the voyage itself and how much came later from isolation on each island.
