In 1993, the Royal Swedish Academy of Sciences awarded the Nobel Prize in Chemistry for work on DNA-based chemistry methods, with one-half of the prize going to Kary Mullis for his invention of the polymerase chain reaction (PCR) method.

His work, the academy said, had "hastened the rapid development of genetic engineering" and "greatly stimulated biochemical research and opened the way for new applications in medicine and biology."

The academy added: "The applications of Mullis' PCR method are already many. It is for example possible using simple equipment to multiply a given DNA segment from a complicated genetic material millions of times in a few hours, which is of very great significance for biochemical and genetic research. The method offers new possibilities particularly in medical diagnostics, and is used, for example, for discovering HIV virus or faulty genes in hereditary diseases."

Here's the academy's press release announcing the award, with more information about PCR.