: The polymerase chain reaction is a technique for cloning a particular piece or amplifying a single or few copies of a piece of DNA, generating millions or more copies of that particular DNA sequence. One can make virtually unlimited copies of a single DNA molecule even though it may initially be present in a mixture containing many different DNA molecules.
A basic PCR requires the following components:
- DNAtemplatethat contains the DNA region called target to be amplified.
- Two primerscomplementary to the DNA regions at the 5′ or 3′ end of DNA.
- The enzyme, Taq polymeraseor another DNA polymerase with a temperature optimum at around 70°C.
- Deoxynucleoside triphosphates (dNTPs)that are building blocks for DNA synthesis, e.g. dATP, dGTP, dCTP and dTTP.
- Buffer solution, providing a suitable chemical environment for optimum activity and stability of the DNA polymerase.
- Divalent cations, magnesium or manganese ions; generally Mg2+ is used but Mn2+ can be utilized for PCR-mediated DNA mutagenesis.
- Monovalent cationpotassium ions.