Researchers find the earliest evidence of domestic...( Maize was domesticated from its wild...)

Maize was domesticated from its wild ancestor more than 8700 years according to biological evidence uncovered by researchers in the Mexico's Central Balsas River Valley. This is the earliest dated evidence -- by 1200 years -- for the presence and use of domesticated maize.

The researchers, led by Anthony Ranere of Temple University and Dolores Piperno of the Smithsonian National Museum of Natural History, reported their findings in two studies -- "The Cultural and chronological context of early Holocene maize and squash domestication in the Central Balsas River Valley, Mexcio" and "Starch grain and phytolith evidence for early ninth millennium B.P. maize from the Central Balsas River Valley, Mexico" -- being published in the PNAS Early edition, March 24.

According to Ranere, recent studies have confirmed that maize derived from teosinte, a large wild grass that has five species growing in Mexico, Guatemala and Nicaragua. The teosinte species that is closest to maize is Balsas teosinte, which is native to Mexico's Central Balsas River Valley.

"We went to the area where the closest relative to maize grows, looked for the earliest maize and found it," said Ranere. "That wasn't surprising since molecular biologists had determined that Balsas teosinte was the ancestral species to maize. So it made sense that this was where we would find the earliest domestication of maize."

The study began with Piperno, a Temple University anthropology alumna, finding evidence in the form of pollen and charcoal in lake sediments that forests were being cut down and burned in the Central Balsas River Valley to create agricultural plots by 7000 years ago. She also found maize and squash phytoliths -- rigid microscopic bodies found in many plants -- in lakeside sediments.

Ranere, an archaeologist, joined in the study to find rock shelters or caves where people lived in that region thousands of years ago. His team carried
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