What are the advantages of real time PCR over traditional PCR?

Question

What are the advantages of real time PCR over traditional PCR?

Answer 1

One of the main advantages of Real-Time PCR is that you can quantitate an exact number of copies of the original template in the sample.  In Real-TimePCR, the thermocycler measures the flourescence given off by the flourophore after each round of amplification.  One can quantify the number of copies of the template by measuring the PCR cyle number when the flourescence passes over a certain threshold.  The samples that pass this threshold first contain more of the original DNA than the ones that pass the threshold later. Commonly, a flourescent dye that intercalates with double stranded DNA is used (ex. SYBR Green).  Overall, Real-Time PCR is incredibly usefull when you need to quantify the starting amount of DNA (or RNA in the case of reverse transcription PCR).