sentences:  For instance, traditional PCR techniques require the use of gel electrophoresis to visualize amplified DNA molecules after the reaction has finished.quantitative PCR does not require this, as the detection system uses fluorescence and probes to detect the DNA molecules as they are being amplified.In addition to this, quantitative PCR also removes the risk of contamination that can occur during standard PCR procedures (carrying over PCR product into subsequent PCRs).