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Polynesia was settled in a series of extraordinary voyages across an ocean spanning one third of the Earth1, but the sequences of islands settled remain unknown and their timings disputed. Currently, several centuries separate the dates suggested by different archaeological surveys2–4. Here, using genome-wide data from merely 430 modern individuals from 21 key Pacific island populations and novel ancestry-specific computational analyses, we unravel the detailed genetic history of this vast, dispersed island network. Our reconstruction of the branching Polynesian migration sequence reveals a serial founder expansion, characterized by directional loss of variants, that originated in Samoa and spread first through the Cook Islands (Rarotonga), then to the Society (Tōtaiete mā) Islands (11th century), the western Austral (Tuha’a Pae) Islands and Tuāmotu Archipelago (12th century), and finally to the widely separated, but genetically connected, megalithic statue-building cultures of the Marquesas (Te Henua ‘Enana) Islands in the north, Raivavae in the south, and Easter Island (Rapa Nui), the easternmost of the Polynesian islands, settled in approximately ad 1200 via Mangareva. Analysis of genomic networks from 430 modern individuals across 21 Pacific island populations reveals the human settlement history of Polynesia.

To investigate the extent of ancient agriculture on Easter Island, this study examines pollen, phytoliths and starch preserved in dryland soils at 11 sites across the island. Taxa are variably represented by different types of microfossils, with Arecaceae and Poaceae over-represented, and dicotyledons, Cyperaceae and ferns under-represented. Phytoliths show better preservation than pollen. The identification of four Polynesian-introduced cultigens, at seven sites, provides botanical evidence for island-wide horticulture. The cultigens identified, Broussonetia papyrifera, Colocasia esculenta, Ipomoea batatas and Musa sp., have differential representation in microfossil spectra, partly because of variable production of microfossil types and amounts, which could give a false impression of the importance of past species. The identification of phenolic inclusions represents a new microfossil type for C. esculenta. Large differences in microfossil proportions at one of the two high-altitude sites compar...