Genetically modified (GM) foods are foods derived from organisms whose genetic material (DNA) has been modified in a way that does not occur naturally through the introduction of a gene from a different organism. Currently, available GM foods stem mostly from plant, but in future foods derived from GM microorganisms of GM animals are likely to be introduced in the market. Most existing GM crops have been developed to improve yield, through the introduction of resistance to plant diseases or of increased tolerance to drought. Some of the GM crops have higher nutritional content too.