NEETZoologyBiotechnology - Principles and Processes
A researcher sets up a standard Polymerase Chain Reaction (PCR) to amplify a gene of interest. However, instead of adding Taq polymerase, they mistakenly add ordinary DNA polymerase isolated from Escherichia coli . All other components (template DNA, primers, and dNTPs) are correctly added. What will be the most likely consequence on the gene amplification process?
Options
- AAmplification will occur but at a much slower rate.
- BThe primers will fail to anneal to the template DNA.
- CNo amplification will occur as the enzyme will be denatured during the first cycle.
- DContinuous amplification will occur but with a high rate of mutations.
Correct answer
C. No amplification will occur as the enzyme will be denatured during the first cycle.
Step-by-step solution
PCR involves three main steps: Denaturation, Annealing, and Extension. The denaturation step requires a high temperature (around 94^ C ) to separate the double-stranded template DNA. Ordinary DNA polymerase from E. coli is not thermostable. It will be denatured and permanently destroyed during the very first high-temperature denaturation step. Consequently, no extension of primers can occur, resulting in no amplification of the gene. This is why Taq polymerase, isolated from the thermophilic bacterium Thermus aquat