Polymerase Chain Reaction (PCR)

Definition

Polymerase chain reaction (PCR) using a method used to amplify a small amount of DNA in order to allow scientist to study it in detail[1]. RNA can also be extracted from samples and converted into complimentary DNA (cDNA) for PCR amplification [4]. Primers are used to identify the location of the DNA in the sample. Enzymes that have defined segments of DNA are taken advantage of to recreate cDNA [4].

Primers

PCR primers are single strands of DNA used to identify the location of the DNA in the sample. This refers to a small set of nucleotides in DNA. For archaea and bacteria primers that are ubiquitous to the 16s ribosomal RNA (rRNA) are used [1,2,3,5,6]

Method

There are three essential steps when conducting PCR.

1. The melting of the target DNA [2]

2. After the DNA has been melted the primers are combined into a synthesized DNA [2]

3. Finally, there is a primer extension by thermostable DNA polymerase [2]

Uses

PCR is used to identify

References

1. Bruce, K.D., Hiorns, W.D., Hobman, J.L., Osborn, A.M., Strike, P., Ritchie, D.A., 1992. Amplification of DNA from native populations of soil bacteria by using the polymerase chain reaction. Applied and Environmental Microbiology 58, 3413–3416. https://doi.org/10.1128/AEM.58.10.3413-3416.1992

2. Henson, J.M., French, R.C., n.d. THE POLYMERASE CHAIN REACTION AND PLANT DISEASE DIAGNOSIS 30.

3. Picard, C., Ponsonnet, C., Paget, E., Nesme, X., Simonet, P., 1992. Detection and enumeration of bacteria in soil by direct DNA extraction and polymerase chain reaction. Applied and Environmental Microbiology 58, 2717–2722. https://doi.org/10.1128/AEM.58.9.2717-2722.1992

4. Schochetman, G., Ou, C.-Y., 2021. Polymerase Chain Reaction 5

5. Tsai, Y.L., Olson, B.H., 1992. Detection of low numbers of bacterial cells in soils and sediments by polymerase chain reaction. Applied and Environmental Microbiology 58, 754–757. https://doi.org/10.1128/AEM.58.2.754-757.1992

6. WILSONl, K.H., Blitchington, R.B., Greene, R.C., 1990. Amplification of Bacterial 16S Ribosomal DNA with Polymerase Chain Reaction. J. CLIN. MICROBIOL. 28, 5.