Differences between PCR and QPCR Methods of Gene Expression - Essay Example

What Tips the Scale: Comparing and Contrasting PCR and QPCR Methods of Gene Expression The polymerase chain reaction (PCR) has revolutionized several facets of routine laboratory work. For instance, it has been utilized for multiple purposes – to quantify mRNA levels (RT-PCR); produce DNA fragments for the purposes of cloning and subcloning; label and identify bacterial colonies; carry out DNA sequencing, specifically differential display cloning (DD-PCR), and library screening (Dharmaraj, S. 2005). Through PCR, the detection of RNA and DNA has fully evolved. Conventional PCR has transitioned from detection or recognition at the end-point of a reaction, to detection while the reaction is transpiring. Real-time chemistries permit the detection of PR amplification early on. Quantification of the kinetics of the reaction at its onset defines the distinguished advantage of QPCR over traditional PCR. Moreover, these conventional methods utilize Aragose gels for detection of PCR amplification at the final stage of the PCR reaction (Dharmaraj, S. 2005; Kawamoto, S., Tadashi, O., Kita, H., Chisaka,O., & Okubo, K. 1999). End-point PCR has several constraints; for one, aragose gel results are obtained at the end of the reaction, which may prove to be very tedious and time-consuming. Results may not be available until after several days. One other advantage of QPCR is its capacity to capture even the slightest differences in the variable sample yields, which may not be as accurately measured through conventional aragose gels. It may also prove to be more difficult because of the very poor resolution of aragose gel, estimated to be about 10-fold (Dharmaraj, S. 2005). In contrast, QPCR is sensitive enough to detect a two-fold change. In summary, the following are the marked disadvantages on the use of traditional PCR: poor precision, low sensitivity, short dynamic range Read More