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This is Scientific American 60-Second Science.I'm David Biello.Got a minute?

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Chestnut trees once carpeted the eastern U.S.

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Three billion of them fed and sheltered many forest residents, until the early decades of the 20th century when a fungal disease called chestnut blight killed almost every last one of the trees.

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But now the American chestnut is making a comeback in its former range—thanks to genetic modification.

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The blight came to the U.S.on imported Asian chestnuts, which are resistant to the disease.

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With that resistance in mind, in the 1980's the American Chestnut Foundation began working to crossbreed the Asian chestnut with surviving individuals of its American cousin.

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Such crossbreeding is time-consuming, however, and results in something less than a full American chestnut.

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In a bid to speed up restoration work and minimize the need for genetic changes,

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scientists at SUNY College of Environmental Science and Forestry have introduced genes into the American chestnut from wheat that help disarm the fungus.

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And, in future, genes from its Chinese cousin, other trees and even grapes could help make the American chestnut even more resistant to the deadly blight.

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A few of the hybrid chestnuts have been planted in the wild from New Jersey to Virginia.

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And test plots of the genetically foritified trees have shown promising results.

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Some environmentalists worry about genetically modified organisms.

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But a bit of genetic tweaking, whether by crossbreeding or gene insertion, looks like the only way to restore the chestnut to its former glory.

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Thanks for the minute, for Scientific American 60-Second Science. I'm David Biello.

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