Different Types of PCR Reagents
Polymerase chain reaction (PCR) is a method for producing DNA fragments from any DNA source that can be replicated by PCR reactions. The DNA sequence isolated in this reaction is identical to the sequence of natural DNA. Different DNA applications, such as cloning and repairing DNA errors, require different sets of primer/ PCR mix and temperature settings. The most commonly used PCR procedures are described below.
Polymerase chain reaction (PCR) is a method to generate multiple copies of a DNA sequence from a single DNA sample. The DNA sequence is replicated using azyme-specific DNA synthesis procedure. Multiple copies of the DNA sequence can be generated by repeated heating at specific temperatures. The exact temperatures and times depend on the type of DNA used and the target sequence. For example, the DNA sequences of living organisms are usually heat-treated in a certain temperature range in order to induce their adhesion to DNA strands and then use the various temperature cycles to generate numerous copies of the targeted sequence.
Another important usage of PCR is to generate precise gene knockouts. This technique is most often used in biotechnological plants where target sequences of Interest are targeted for evolution or expansion. There are two primary methods employed to employ PCR in this context: tandem repeats and transcription mediated amplification (TMA). TMA is a highly efficient technique; however, it generates a lot of repetitive sequences (usually tens to hundreds of sequences) that are prone to frequent base sequencing errors.
Another highly useful application of PCR is in the field of genetic analysis. PCR amplifies specific genes by heating individual DNA strands in the presence of the primer, followed by digestion with polymerase and checking the resulting product for sequence abnormalities. The primer used in this process is designed to specifically generate the target sequence. PCR amplifies the target sequence within the host organism (this is known as restriction fragment length).
The third widely used PCR method is the use of EcoRIgenic Polymerase (EPC). EPC is a highly specific and sensitive form of PCR that allows for precise and rapid amplification of short, long, and mixed sequences respectively. It is also capable of detecting and characterizing genetic differences in living organisms (genetic fingerprinting). The use of EPC results in the formation of multiple copies of the target sequence on the same strand of DNA material. This greatly increases the odds of creating error-free genetic fingerprints.
Apart from these three commonly used techniques, there are a few other novel techniques that have been developed and are currently being used for genetic fingerprinting. Another technique involves amplifying DNA fragments using restriction enzyme that has been specially engineered to specifically generate restriction fragments specific to a set of DNA templates. This technique can greatly increase the accuracy of paternity testing.