Kahiki means Tahiti, yet Hawaiian genomes trace to Mangareva

About 7,000 km of open ocean separates Hawaiʻi from Rapa Nui. A genome comparison published on 8 October found the 2 islands more closely related to one another than to the other populations of Polynesia. Population geneticists from Stanford and San Diego drew on 1,050 genomes from 5 French Polynesian archipelagos and 12 new genomes from Rapa Nui. The team took Native Hawaiian records from a National Institutes of Health biobank. Samoans and Tongans from that biobank gave the western reference. Out of 2,500 bootstrapped trees, Hawaiʻi formed an immediate pair with Rapa Nui in 61%.

From island to island, founder effects compound. A canoe crew founding an island brings a fraction of the genetic variation found at home. Rare variants then climb in frequency among its descendants. The team scored shared inherited segments between islanders and found Polynesian scores at least an order of magnitude above those of Finland, a widely studied founder population. Its estimate for Tahiti from 581 Society Islanders puts the founding bottleneck at an effective size of 837 people around 1069 AD. Carrier frequencies for 3 recessive-disease variants in French Polynesia came out between 2.22% and 3.68%.

The authors call the voyagers behind the pairing Holomoana Nui (great ocean voyaging), a Hawaiian name of their own choosing. Their trees give the group deeper roots in Mangareva and put the Marquesas at the base of the clade. Hawaiʻi paired with Mangareva in 10.45% of the trees and with the Marquesas in 2.75%. The acknowledgments thank the Mata Ki Te Rangi Foundation on Rapa Nui. They also address the people of Moananuiākea (the Pacific Ocean, in Hawaiian usage). It is the authors themselves who set their genetic tree beside a linguistic tree drawn 60 years earlier.

In 1966 Roger Green published a subgrouping of the Polynesian languages in the Journal of the Polynesian Society. He placed Hawaiian, Mangarevan and Marquesan in a Proto-Marquesic subgroup and treated Rapa Nui as a close outlier. A second subgroup, Proto-Tahitic, joined the languages of 3 archipelagos. Green put the Austral Islands, the Society Islands and the Tuamotus in it. The 2026 identity-by-descent tree does split the islands along Green's line. Matisoo-Smith's team had already paired Hawaiʻi with the Marquesas in 1998 from Polynesian rat DNA.

Russell Gray, Alexei Drummond and Simon Greenhill of the University of Auckland applied tree-building methods from evolutionary biology to the basic vocabulary of about 400 Austronesian languages. Their 2009 trees put the origin of the family in Taiwan about 5,200 years ago. The trees also show 2 long pauses in the expansion. Speakers stayed about 1,000 years in Taiwan. A second pause of about 1,000 years followed the founding of Fiji, Samoa and Tonga.

In Europe, Wolfgang Haak and colleagues generated genome-wide data in 2015 from 69 Europeans dated to between 8,000 and 3,000 years ago. Late Neolithic Corded Ware people from Germany traced about 75% of their ancestry to the Yamnaya of the steppe. The authors took the result as support for a steppe origin of at least some Indo-European languages of Europe. The team did not claim proof. The abstract dates the contact between Western and Eastern Europe to about 4,500 years ago.

Linguists define a subgroup by its shared innovations, a term for sound changes made by an ancestral speech community and inherited by its daughter languages. The Marquesan documentation project of the DOBES programme dates the innovations shared by North and South Marquesan to around the 10th century AD. Speakers call the northern variety ʻeo ʻenana (North Marquesan) and the southern variety ʻeo ʻenata (South Marquesan). On ʻUa Pou, speakers retain the old *k and say kite (see, know). Speakers on Nuku Hiva and Hiva ʻOa say ʻite, with a glottal stop in the place of the consonant.

A museum commissioned a curatorial response to a carved figure in North Marquesan. Because the contributor's community uses French, a translator drafted an in-house French version as a check on sense. The translator then wrote the North Marquesan text and compared it with the English and the French. A South Marquesan word form in the North Marquesan text would have attributed southern speech to a northern community. The translator kept the motif names in Marquesan and matched the cautious, interpretive wording of the English.

The Polynesian Lexicon Project, POLLEX, reconstructs a Nuclear Polynesian name *sawaiki (traditional homeland) and lists 17 entries under it. Samoan Savaiʻi names an island. Māori Hawaiki names the traditional homeland. In Tahitian, Havaiʻi (an old name for Porapora) attaches the word to the island charted in English as Bora Bora. In Tongareva speech, Savaiki gives an older name for Raʻiatea. UNESCO inscribed the marae (sacred ceremonial and social space) of Taputapuātea on Raʻiatea in 2017 and places the island at the centre of the Polynesian Triangle.

There is an underworld sense in the eastern entries. Mangarevan ʻAvaiki (Hawaiʻi, a place named in Mangarevan chants and legends) also denotes a deep place. POLLEX lists the northern Marquesan form as havaiki and the southern form as havaiʻi. The entry glosses the 2 forms as underground places, the mythic country of the first humans, to the west toward the setting sun.

Rapa Nui oral tradition names Hotu Matuʻa as the founding chief and Hiva as his homeland. In the account, the royal adviser Hau Maka dreamed of an island called Mata ki te Rangi (eyes looking to the sky). Linguistic comparison of Rapa Nui with its neighbours makes the Marquesas the likely Hiva. The island name Te Pito o te Henua means the centre of the earth. Some historians see a borrowing in the chief's name, close to Atu Motua (a Mangarevan founder god). They date its addition to the 1860s and link it to the arrival of Mangarevan speech.

The authors drew the French Polynesian genomes from the Maʻi uʻu epidemiological survey cohort. The Direction de la Santé in Papeʻete appears among the author affiliations. French public-health law classes such studies as recherche impliquant la personne humaine (research involving the human person). In its commentary on Article R.4127-15 of the Code de la santé publique, the Ordre des médecins names consentement libre et éclairé (free and informed consent) as a point of particular insistence in the law. The authors list Indigenous data sovereignty among the commitments of their partnerships.

In the 1986 Pukui-Elbert dictionary, the Hawaiian Kahiki means Tahiti. Their dictionary glosses lower-case kahiki as a foreign country, or abroad. However, the genome trees give Hawaiʻi founders from the Mangareva line and put Tahiti in the other cluster. The authors accept voyaging and trade between islands after the founding. Exponential growth in the first generations amplified the share of the founding crews in the gene pool. Newcomers from distant islands would have needed orders of magnitude more people than the dozens of passengers on a double-hulled sailing canoe.