From cucumbers and carrots to white rice and wheat, humans have altered the genes of almost every food we eat. For almost 10,000 years we've been selectively breeding or engineering (changing) plants by keeping the seeds from the best crops and planting those the next season. We've also been altering the genetic makeup of crops by cross-pollinating. About 8,000 years ago, for example, farmers in Central America crossed two mutant strains of a weedy-looking plant called Balsas teosinte and produced the first corn on the cob.
More recently species have been changed, by adding genes from completely different species. Plants and animals with added genes from other organisms are called genetically modified organisms (GMOs). For example, the DNA is some tomatoes now has genes (little piece of DNA) from fish. What is different in GMOs from other engineered crops is that the traits are new to this organism, not something that developed from mutation in the environment and was emphasized by selective breeding.
In this following simulation you will compare and contrast two different ways of manipulating species that we eat. The first, selectively breeding, has been occurring for thousands of years. The second, genetically modifying species, has been around for only a few decades.
Engineering Crops Comparison Table 1.1