However, Taq was eventually found to be susceptible to errors in complementary base pairing during primer extension (see section on PCR protocol); and although the Taq polymerase is still used, many investigators currently prefer to use the DNA polymeruse cloned from Pyrococcus furiosus (Pfu), an organism that grows optimally in geothermal marine sediments at 100 [degrees] C.
This is achieved by heating the dsDNA at 94 [degrees] C for 1 minute, disrupting the hydrogen bonds required for complementary base pairing. The resulting two ssDNA molecules permit the bases of each strand to undergo annealing to primers, during which new hydrogen bonds form between the complementary bases of the primers and ssDNA.