Polymerase Chain Reaction is a technique used to amplify a specific region of a DNA molecule to generate multiple copies. This innovative technology was developed by American biotechnologist Kary Mullis in the year 1983. He was awarded with noble prize for his innovative work in 1993 (Singh et al., 2014). The important component of PCR include:
- 1. Template DNA: Target DNA molecule to be amplified
- 2. Taq polymerase: a DNA polymerase enzyme isolated from bacterium ‘Thermus aquaticus’ used for replication process. It is a thermostable enzyme which can sustain its activity at a wide range of temperatures.
- 3. Oligonucleotide primers: a short sequence of DNA which are complementary to the template DNA and serve as a DNA synthesis starting point. These are designed specifically for the amplification of region of interest.
- 4. Deoxyribonucleotide triphosphates (dNTPs): are the building blocks required for replication of DNA. Adenine (A), guanine (G), cytosine (C), and thymine (T) are the four different dNTPs used in the reaction. DNA polymerase adds each complementary base to the new growing DNA strand according to the original template.
- 5. PCR Buffer: The reaction mixture contains the buffer which provide the optimum pH for the PCR. Magnesium is another important constituent of the PCR cocktail which acts as a cofactor regulating the activity of Taq DNA polymerase.