An American nurseryman introduced the Japanese chestnut tree to the eastern U.S., accidentally introducing a blight fungus along with it. The fungus essentially wiped out the entire American chestnut population.
In 2006, biologist William Powell, director of the American Chestnut Research & Restoration Program, transferred a single wheat gene into the cells of a blight-stricken tree. The simple gene is also found in strawberries and barley. It makes the plants more resistant to the fungus that causes blight.
Powell began growing the transgenic American chestnut trees in his lab. Genetically, they were all but identical to the wild-type American chestnut — both trees had the same 40,000 genes. But the transgenic chestnut has one extra. That solitary gene could save the species.
But to get regulatory approval to introduce the tree into the wild, Powell had to convince the federal government that the transgenic tree is barely any different from the wild type, in every way imaginable.
“We look at all these things to make sure that what we really have is an American chestnut tree. And the only thing added to it is the ability to detoxify the acid that the fungus uses to attack,” he says, adding that, so far, everything checks out a-OK.