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 forests—where the plant was grown—made contact with people in the highlands—where 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.