WASHINGTON (AP) — As millions of Americans cook a traditional Thanksgiving meal, the Smithsonian Institution offers some history about that food’s origins.

Scientist Bruce Smith says many dishes eaten Thursday have roots in Mexico and South America. He says turkeys were domesticated twice — in central Mexico and in the U.S. Southwest. Turkeys eaten nowadays are derived from the Mexican turkeys.

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At the first Thanksgiving, wild turkeys were eaten. Smith says domesticated turkeys likely were taken from Mexico to Europe and then introduced to the United States by settlers.

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Potatoes were domesticated in South America, likely Peru. But Europeans likely brought them to the U.S. Squash, pumpkins and corn likely spread by trading among American Indian tribes.

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Cranberries are native to the U.S. American Indians first used them as food.
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