Biotechnology is the use of cells or whole living organisms to produce materials useful to people, such as foods, medicines, and chemicals. People have been using various forms of biotechnology for a long time. For example, the use of yeasts to brew beer and wine dates back at least 8,000 years, and the use of bacterial cultures to make cheese and yogurt is a technique many centuries old. For a long time people exploited these biochemical transformations without being aware of the organisms and genes involved. Today with recombinant DNA techniques, almost any gene can be inserted into bacteria, yeasts, mammalian cells, plant cells, or even whole organisms, inducing them to make a gene product in large amounts.