Thermus aquaticus colonies, Emerald Pool
hot spring, Yellowstone National Park
polymerases used in the polymerase chain reaction were originally
isolated from naturally-occurring bacteria (such as T. aquaticus) that grow
in near-boiling water of hot springs (90 ~ 100 oC).
and other proteins in these "extremophile"
organisms have adapted evolutionarily to be stable and
functional at high temperature. Temperature-resistant DNAPols are
now genetically engineered to possess the particular
properties required for optimal PCR.