Fourth in a five-part series about genetically modified crops.
For the past two decades, promises of crop improvement have been the domain of genetically modified plants: mostly, crops supplemented with bacterial genes to resist pests or weedkillers like Roundup. More than 85 percent of U.S. corn, soy or cotton grown contains such genes.
But there is more than one way to transform a plant.
Using advanced biotechnology, long hidden in the background and only now starting to pay dividends, scientists are changing crops without tapping foreign genes -- and often without the regulatory oversight that is given to GM crops.