From Dan Garisto at Science News:
New genetic evidence instead suggests that wild precursors to sweet potatoes reached Polynesia at least 100,000 years ago — long before humans inhabited the South Pacific islands, researchers report April 12 in Current Biology. If true, it could also challenge the idea that Polynesian seafarers reached the Americas around the 12th century.
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The researchers calculated the average rate of genetic change for the plant, determining that the Polynesian sweet potato diverged from its South American cousin at least 100,000 years ago. That suggests the plants, or their seeds, somehow migrated across the ocean on their own, possibly via wind, water or birds. Precedent exists, the authors note. Two other Ipomoea species crossed the Pacific millions of years ago — to Hawaii in one case, and to islands from Polynesia to Madagascar in the other.
“It could be true,” says biological anthropologist Lisa Matisoo-Smith of the University of Otago in New Zealand. But she and other researchers remain dubious about the findings. Among the issues, the analysis involved just a single historical sample. More.
It does seem a long journey for the humble sweet potato. But we shall see.
See also: Earlier than thought: Dogs lived with humans in the Americas 10 kya Burial of dogs who died from natural causes implies, of course, a level of affection and esteem.
and
Biogeography: Monkeys sailed the ocean blue?