解密椰子的传播历史

The coconut (the fruit of the palm Cocos nucifera) is the Swiss Army knife of the plant kingdom; in one neat package it provides a high-calorie food, potable water（饮用水） , fiber that can be spun（纺，旋转） into rope, and a hard shell that can be turned into charcoal（木炭） . What's more, until it is needed for some other purpose it serves as a handy flotation device. No wonder people from ancient Austronesians to Captain Bligh pitched a few coconuts aboard before setting sail. (The mutiny兵变，叛乱 of the Bounty is supposed to have been triggered by Bligh's harsh punishment of the theft of coconuts from the ship's store.)

So extensively is the history of the coconut interwoven with the history of people traveling that Kenneth Olsen, a plant evolutionary biologist, didn't expect to find much geographical structure to coconut genetics when he and his colleagues set out to examine the DNA of more than 1300 coconuts from all over the world.

"I thought it would be mostly a mish-mash," he says, thoroughly homogenized（使均匀，使类同） by humans schlepping coconuts with them on their travels.

He was in for a surprise. It turned out that there are two clearly differentiated populations of coconuts, a finding that strongly suggests the coconut was brought under cultivation in two separate locations, one in the Pacific basin and the other in the Indian Ocean basin. What's more, coconut genetics also preserve a record of prehistoric trade routes and of the colonization of the Americas.

The discoveries of the team, which included Bee Gunn, now of the Australian National University in Australia, and Luc Baudouin of the Centre International de Recherches en Agronomie pour le Développement (CIRAD) in Montpellier, France, as well as Olsen, associate professor of biology at Washington University in St. Louis, are described in the June 23 online issue of the journal PLoS One.