History
The invaluable molecular technique known as PCR, or the polymerase chain reaction, was discovered by a biochemist named Kary Mullis. Mullis was doing research in the early 1980s at a biotechnology company in California when he initially thought of the idea regarding PCR. PCR was developed by a combination of several techniques already in existence; the synthesis of oligonucleotides and their utilization to synthesize new copies of DNA that were specific using DNA polymerases. Mullis specifically used two oligonucleotides that were each complementary to an opposite strand of the DNA (Bartlett, 2003). This allowed the region in between the oligonucleotides to become amplified and Mullis did this in repetition, allowing the product formed from DNA polymerase activity in a single round to be used in the next round as a template. This original method of PCR was further modified and developed by Mullis and his colleagues at Cetus Corporation. The original DNA polymerase used …show more content…
Tubes containing samples can then be placed inside the thermocycler to initiate the reaction. The sample in a tube may contain the following: 10 x PCR buffer (creates a suitable environment for optimum enzymatic activity), 2 mM dNTP mix (the building blocks of new DNA strands), 2 oligonucleotide primers (used to amplify the target DNA fragment), Taq polymerase (aids in catalyzing the addition of dNTPs onto the DNA strand), 25 mM magnesium chloride (an essential cofactor for Taq DNA polymerase and influences its enzymatic activity), and the template DNA (contains the target fragment in which we want to amplify). The tubes containing the samples are then placed inside the thermocycler, which heats the samples to 94°C - 96°C for 5 minutes and activates Taq DNA polymerase. The double-stranded DNA fragment then denatures at this temperature and forms single-stranded