In this article we will discuss about the applications of PCR.
i. Detection of mutations:
PCR is useful for detection of mutations related to genetic disease including point mutations, insertions and deletions. A notable example is that of the human dystrophin gene associated with Duchenne muscular dystrophy.
The large-sized dystrophin gene consists of about two million base pairs located on the X chromosome. Male patients affected with Duchenne muscular dystrophy have deletions in the exons (protein-coding regions) of dystrophin gene.
ii. Detection of HIV:
PCR can detect bacterial or viral infection from very small samples of cells. In the case of HIV, DNA isolated from peripheral blood cells can be subjected to PCR using primers designed specifically against HIV sequences. PCR amplification followed by gel electrophoresis could reveal presence of the appropriate sized PCR product and HIV infection.
iii. Prenatal Diagnosis:
PCR has proved to be of paramount importance for prenatal diagnosis of genetic disease. DNA extracted from small amounts of foetal tissue can be used for PCR. The same is true for forensic sciences. The enormous sensitivity of PCR-based procedures is useful for DNA profiling.
iv. In Forensics:
Amplification is carried out from trace amounts of DNA in samples such as hair, blood or semen collected from the crime scene. Amplified DNA can be analysed and compared with DNA from a victim and a suspect and results used in criminal investigation. This analysis or DNA profiling is called DNA typing or DNA fingerprinting.
v. Gene Manipulation:
Following amplification, there is scope for altering the amplified sequence by incorporating extra sequences at the ends of the amplified DNA. In fact there are many applications of PCR in gene manipulation.
vi. Fossils and Archaeology:
PCR has potential in identification of organisms that became extinct a million years ago by amplification of very old (ancient) DNA. The high level of sensitivity of PCR is demonstrated when signals are produced from cell samples and degraded DNA from ancient biological samples stored in museums.