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How the humble bottle gourd got to the New World
Traci Watson, Special for USA TODAY 3:04 p.m. EST February 10, 2014
A new study helps explain how the humble bottle gourd made its way to the New World more than 10,000 years ago.
http://www.usatoday.com/story/tech/2014 … d/5260193/
A historical society enthusiast in the role of a French artillery soldier fighting under Napoleon arrives with a musket and water gourd to re-enact The Battle of Nations on its 200th anniversary on Oct. 20, 2013, near Leipzig, Germany.(Photo: Sean Gallup, Getty Images)
If you lived in the New World a thousand years ago, you seldom left home without your bottle gourd. This sturdy fruit makes a handy canteen and tote bag, making it the go-to accessory in prehistoric America. But no wild version grows in the Americas. So how did the gourd get there?
A new study suggests an answer: It floated. Genetic data and ocean-current analysis show the gourd may have drifted across the ocean from Africa to the Americas, then grew wild before early Americans started to domesticate it about 10,000 years ago. The study's results, if confirmed, would resolve a long-standing mystery related to one of the most momentous events in the New World — the invention of farming.
"The bottle gourd's always been an anomaly. It's been puzzling people for a long time," says Bruce Smith, an expert in American plant domestication at the Smithsonian Institution's National Museum of Natural History and an author of the new study. In light of the new results, "the bottle gourd is no longer an anomaly."
In the days before Columbus, no plant trotted the globe like the bottle gourd. It was used as a children's swimming aid in the Roman empire and as a pontoon in Egypt, as a fishing-net float in ancient Peru and as a musical instrument in Africa. How it got so far has intrigued scientists.
A genetic study published a decade ago concluded American gourds originated in Asia, leading to speculation that colonizers from Asia had carried domesticated gourds across a now-vanished land bridge to Alaska. But that would've required the plant to survive in places too cold for it.
Another scientific team has reanalyzed the bottle gourd's genetics, looking at its DNA in more depth than was possible 10 years ago. The scientists found that contrary to the earlier research, American gourds actually come from African stock. Next, the team ran computer models showing what happens to gourds bobbing in the sea off Africa. A good number make it to South America after less than a year, a voyage short enough for the gourd seeds to sprout after making landfall. The work appears in this week's Proceedings of the National Academy of Sciences.
The results help vindicate Native Americans' ability to domesticate plants on their own, Smith says. The earlier thinking that the gourd was already domesticated when it reached the New World could, in theory, be used to argue that the idea of plant domestication came from outsiders, rather than being home-grown. The new results showing the gourd came over as a wild plant are "comforting," he says.
Some are unconvinced by the new results. The genetic analysis didn't include any ancient gourds from Asia, points out Hanno Schaefer of Germany's Technical University of Munch, a botanist who specializes in squashes and gourds. That omission means the analysis could have missed something, he says. Schaefer wonders why, if wild gourds can easily make it all the way from Africa to the Americas, they don't grow in the New World now.
"I do now believe bottle gourds didn't come with Asian colonizers," Schaefer says. "But I still think that what they have is not enough to tell us what happened."
Study author Logan Kistler, a post-doctoral researcher at Pennsylvania State University, responds that his team would like to get more data from ancient Asian gourds. Kistler points to changes in climate and the extinction of animals such as the mastodon, which may have spread the gourd's seeds in their dung, to explain why bottle gourds don't grow wild in the Americas. The gourd, he says, remains "enigmatic."
"It's so widespread so early on, and it's used so cross-culturally," says Kistler, a molecular anthropologist. "We have much more to learn about this species."