Real time PCR is based on the detection of the fluorescence produced by a reporter molecule which increases, as the reaction proceeds.
This occurs due to the accumulation of the PCR product with each cycle of amplification which leads to increased fluorescence.
These fluorescent reporter molecules include dyes that bind to the double-stranded DNA (i.e.,SYBR® green) or sequence specific probes (i.e.,Molecular beacons or taqman® probes).
Advantages of Real Time PCR:
Minimal amounts of nucleic acid required to quantify the results accurately
Post PCR processing is not needed which saves the time and resources
Real time PCR assays have high sensitivity and more specificity
Minimal risk of cross contamination
These advantages of the fluorescence based Real time PCR technique have completely revolutionized the approach to PCR-based testing of DNA and RNA.