In order to gain information about the DNA, different types of the PCR is often the starting point in series of experiments.
The usual way of analyzing the products of the PCR reaction is to separate the samples in an agarose electrophoresis gel. A band representing the amplified DNA may be visible after staining.
Agarose gel electrophoresis can be used to obtain additional information, besides to determine if a PCR experiment has worked.
Treating the PCR product with a restriction endonuclease before running the sample in the agarose gel can help to detect the presence of restriction sites in the DNA template. This restriction fragment length polymorphism (RFLP) analysis is important for the construction of genome maps and studying genetic diseases.
The size of the PCR product can be used to determine if the DNA template contains an insertion or deletion mutation in the amplified region. This type of mutations is the basis of DNA profiling – one of the techniques in forensic science.
The presence or absence of the PCR product can be the diagnostic feature. For example, PCR is used as the screening procedure to identify the desired gene from a genomic or cDNA library, or for the detection of pathogenic microorganisms in a clinical specimen.
Another two particularly important techniques for studying PCR products include cloning and sequencing of PCR products.
Some applications of polymerase chain reaction include:
- the identification of the owner of a DNA sample left at a crime scene;
- paternity analysis;
- the comparison of small amounts of ancient DNA with modern organisms;
- determining the sequence of nucleotides in a specific region.
Different PCR techniques and their application
