The Hot Springs Connection

Polymerase is the chemical that a cell uses to replicate its DNA when it divides. The polymerase attaches to a single strand of DNA after the molecule splits and builds a complementary strand to re-create the double helix. Polymerase chain reaction (PCR) takes advantage of this mechanism to make many copies of a small DNA section.

An early limitation on PCR was the fact that the polymerase broke down when the solution was reheated in order to split the strands again. The problem was solved when Kary Mullis and his colleagues at Cetus discovered that they could use a form of polymerase from a bacterium that lived in the scalding water of Yellowstone National Park hot springs. This chemical,called Taq polymerase (after Thermus aquaticus, the name of the bacterium), can withstand high temperatures and has the ability to replicate human DNA. The PCR solution can be reheated over and over without adding chemicals.

Taq polymerase was named Molecule of the Year by Science magazine in 1989. It sped up the PCR process and made automation much easier.