for National Geographic News
An ancient culture in southern Peru cultivated corn some 4,000 years ago, about a thousand years earlier than previously believed, a new study suggests.
Researchers excavating a site in the Andean highland town of Waynuna found both corn leaf and corncob remains in the ruins of a house at least 3,600 years old.
Perhaps even more important, the scientists say, is that they found arrowroot remains at the same dig site.
The presence of this edible root confirms archeologists' suspicions that people in the eastern lowland forestswhere the plant was grownmade contact with people in the highlandswhere the root was consumed.
"Archaeologists have suspected that there was an important connection between the two areas based upon iconographic evidence and some coastal finds," said Linda Perry, the lead author on the study.
Perry is an archaeobiologist with the Smithsonian National Museum of Natural History in Washington, D.C. She conducted the research with Dolores Piperno, a staff scientist at the Smithsonian Tropical Research Institute in Panama and a National Geographic Society grantee.
Perry added that "our arrowroot fossils are the first highland evidence documenting this connection. Our finds indicate that the connection was early and of long duration."
She and her team describe their findings in this month's issue of the journal Nature.
The Waynuna site, excavated by a team from the University of Maine in Orono, lies in Peru's Cotahuasi Valley, about 200 miles (320 kilometers) west of Lake Titicaca (see map). The area has been occupied since about 13,000 years ago.
Human cultivation of corn probably first began in Mexico almost 10,000 years ago. Then people carried it south to Ecuador by about 7,000 years ago.
In Peru, "our dates indicate a migration of the crop down the Andean mountain chain and an acceptance of maize into the local diet quite early, by 4,000 years ago," Perry said.
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