Technique for inserting a foreign gene into laboratory cultures of bacteria to generate commercial biological products, such as synthetic insulin, hepatitis-B vaccine, and interferon. It was invented 1973 by the US scientists Stanley Cohen and Herbert Boyer, and patented in the USA 1984. See genetic engineering. Cohen was working at Stanford University and Boyer at the University of California. Cohen shared a 1989 Nobel Prize for Physiology or Medicine for his work in cell growth.