https://www.theguardian.com/world/2020/jul/08/indigenous-americans-polynesians-dna-800-years-ago
Not terribly surprising, but neat. 8)
The time around AD 1200 seems to have been the high point of Polynesian voyaging; it's also the timeframe when they spread out across the more distant archipelagos. If I remember right, Kirch blames climate change for the lack of further contact with S America and the isolation of Hawaii and Easter Island from the rest of Polynesia.