One well-known example of genetic modification is the creation of Bt corn. Bt corn is a genetically modified organism (GMO) that has been engineered to express a bacterium's toxin, specifically from Bacillus thuringiensis (Bt). This toxin is responsible for protecting the corn plants from certain pests, such as the European corn borer.
The modification allows the corn to produce a protein that is toxic to these pests when they ingest it, reducing the need for chemical pesticides and helping to increase crop yields. Bt corn has been extensively studied and is widely used in agriculture in various countries.