American biochemist Kary Mullis designed polymerase chain reaction (PCR), a fast and effective technique for reproducing specific genes or DNA fragments that is able to create billions of copies in a few hours. Mullis invented the technique in 1983 while working for Cetus, a California biotechnology firm. After convincing his colleagues of the importance of his idea, they eventually joined him in creating a method to apply it. They developed a machine that automated the process, controlling the chain reaction by varying the temperature. Widely available because it is now relatively inexpensive, PCR has revolutionized not only the biotechnology industry, but also many other scientific fields and it has important applications in law enforcement, as well as history. Mullis shared the 1993 Nobel Prize in chemistry with Michael Smith of the University of British Columbia, who also developed a method for manipulating genetic material.

Kary Banks Mullis was born in...