What method did Kary Mullis help develop, earning him the 1993 Nobel Prize in Chemistry?

Kary Mullis helped develop the polymerase chain reaction, earning the 1993 Nobel Prize in Chemistry.

Polymerase chain reaction, usually called PCR, amplifies selected sections of DNA. Repeated cycles of heating, primer binding, and DNA synthesis can produce millions or billions of copies from a tiny starting sample. This made genetic analysis much faster and more practical.

Mullis conceived the basic PCR idea in 1983 while working at Cetus Corporation. The method became especially effective after scientists adopted the heat-stable enzyme Taq polymerase, obtained from the bacterium Thermus aquaticus.

Mullis shared the Chemistry prize with Michael Smith, who was honored for developing site-directed mutagenesis. PCR is used in medical testing, forensic science, research, and infectious-disease diagnostics. It is not the same as DNA sequencing, which determines the order of bases rather than simply amplifying a target region.