A genetically modified organism, or GMO, is an organism whose genetic structure has been altered by incorporating a single gene or multiple genes—from another organism or species—that adds, removes, or modifies a trait in the organism by a technique called gene splicing. An organism that has been genetically modified—or engineered—to contain a gene from another species is also called a transgenic organism (because the gene has been transferred) or a living modified organism (LMO). Most often the transferred gene allows an organism—such as a bacterium, fungus, virus, plant, insect, fish, or mammal—to express a trait that enhances its desirability to producers or consumers of the final product.

Overview

Plants and livestock have been bred for desired qualities (selective breeding) for thousands of years—long before people knew anything about the science of genetics. As technology advanced, however, so...