Genetically modified organisms are produced when one or more genes are inserted into a food crop. Transgenic is the term used when a gene is taken from one species of plant or animal and inserted into another. Roundup Ready soybeans have a gene taken from a bacterium that protects the soybean plant when Roundup herbicide is applied, allowing the soybean to survive when the weeds surrounding it die. Roundup Ready corn is also marketed. Bt corn is named for bacillus thuringiensis , a bacterium from which a protein gene is taken and engineered into the corn.
Bt cotton repels the boll weevil.
Ironically, organic farmers, among the most vocal critics of GM crops, began spraying the Bt bacterium as a natural alternative to chemical pesticides some 40 years ago. StarLink corn uses a different genetically altered protein to repel the corn borer. Unlike Bt corn, Starlink corn has not been approved for human consumption because of concerns it could cause allergies. Genetically altered tomatoes, potatoes, canola, squash and papaya are also grown. The U.S. Department of Agriculture estimates nearly two-thirds of this year's soybean crop will be Roundup Ready or other biotech varieties.