 The DNA polymerases initially employed for in vitro experiments presaging PCR were unable to withstand these high temperatures.So the early procedures for DNA replication were very inefficient and time-consuming, and required large amounts of DNA polymerase and continuous handling throughout the process.The discovery in 1976 of Taq polymerase—a DNA polymerase purified from the thermophilic bacterium, "Thermus aquaticus", which naturally lives in hot () environments such as hot springs—paved the way for dramatic improvements of the PCR method.