Polymerase Chain Reaction Applications

The polymerase chain reaction (PCR) has dramatically transformed scientific research and diagnostic medicine. Over the years, PCR has become an indispensable and integral part of clinical and diagnostic research. The PCR technique and its several advanced variants act as powerful tools which enable a multitude of specialized applications which were once deemed impossible by the scientific world.

Applications of PCR in Various Scientific Disciplines

Some of the key applications of PCR in the field of genetic research, medicine, forensic science, and environmental microbiology are briefly discussed below.

Genetic Research

PCR has revolutionized scientific research, ever since it was first presented to the outside world in the 1980s. Some of its specialized applications in genetic research are:

• Rapid amplification of tiny fragments of DNA using PCR enabled several techniques such as southern or northern blot hybridization even when the amount of sample material available was very small.
• Study of gene expression patterns is another common application of PCR, where in cells or tissues are analyzed in different stages to check for expression of a specific gene. qPCR can be used here to quantitate the level of gene expression.
• PCR also assists techniques like DNA sequencing using which segments of DNA from an area of interest can be easily amplified to study genetic mutations and their consequences.
• The Human Genome Project used PCR to indicate the presence of a specific genome segment in a particular clone. This enabled mapping of the clones and collating results from several laboratories.
• Advanced variants of the PCR technique have been found to be useful in chromosomal analysis techniques that can help in early detection of genetic birth defects in children.
• PCR augments the traditional method of DNA cloning by amplifying tiny DNA segments for introduction into a vector. By altering the PCR protocol, site-directed or general mutations can be achieved in the DNA fragment of interest.

Medicine

PCR triggered many valuable developments in several medical disciplines.

Microbiology

PCR is a highly valuable technique in microbiology as it allows crucial observations for organism detection. Organisms such as Mycobacterium tuberculosis can be studied effectively with the help of genotyping. This allows early identification and treatment and greatly impacts public health monitoring.

Virology

In virology, PCR helped detect and characterize the nucleic acids of viruses, which enabled comprehensive viral characterization and a greater understanding of the virus behavior during infection. This understanding immensely helped clinical treatment and enhanced further research on the viruses. For instance, PCR is used to detect HIV infection at an early phase even before the antibodies are formed. This is also useful for screening blood samples collected for donation.

Mycology and Parasitology

PCR technology has also found applications in mycology and parasitology, by enabling early identification of the microorganisms, thus aiding efficient diagnosis and treatment of fungal and parasitic infections.

Dentistry

The PCR technique has become a standard diagnostic and research tool in the field of dentistry. PCR and other molecular biology techniques enable the diagnosis of infectious microbes that cause maxillofacial infections. This helps in the effective management of conditions such as periodontal disease, caries, oral cancer, and endodontic infections.

Forensic Science

With the advent of PCR-based DNA fingerprinting, PCR became an invaluable tool in forensic investigations.

• Using DNA fingerprinting, tiny fragments of DNA can be isolated from a crime scene and compared to a huge database of DNA of convicts or criminals. It is also useful in ruling out suspects as part of an investigation.
• DNA fingerprinting is also used in paternity testing, where the DNA from an individual is matched with that of his possible children, siblings, or parents.

Environmental Microbiology

The PCR technique has been successfully used to explore many issues in environmental microbiology. Some of its environmental applications are listed below:

• Sensitive detection of degrading microorganisms in toxic waste and pollutants can be achieved using PCR, which helps efficient biodegradation and bioremediation at the polluted sites.
• A gene probe-based PCR method has been developed by researchers for the detection of indicator bacteria such as coliforms in water supplies, thus supporting measures that enhance water safety.
• PCR is also used to detect and monitor water-borne microbial pathogens, which pose a major public health hazard.

References

• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3209897/
• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768498/
• http://genome.cshlp.org/content/1/3/151.full.pdf

Further Reading

• All Polymerase Chain Reaction Content
• The Polymerase Chain Reaction
• Digital PCR and Traditional PCR: What’s the Difference?
• History of Polymerase Chain Reaction (PCR)
• What is Real-Time Quantitative PCR (qPCR)?

Written by

Susha Cheriyedath

Susha has a Bachelor of Science (B.Sc.) degree in Chemistry and Master of Science (M.Sc) degree in Biochemistry from the University of Calicut, India. She always had a keen interest in medical and health science. As part of her masters degree, she specialized in Biochemistry, with an emphasis on Microbiology, Physiology, Biotechnology, and Nutrition. In her spare time, she loves to cook up a storm in the kitchen with her super-messy baking experiments.