What are the methods used to measure the DNA application in qPCR?

qPCR or real-time PCR, determines the actual amount of PCR product present at a given cycle. The two most common methods used to measure the DNA application in qPCR involve the use of fluorescent dyes and sequence-specific DNA probes. 

Fluorescent Dyes

In this method, DNA application in qPCR is measured using fluorescent dyes such as SYBR Green, which non-specifically intercalates with double-stranded DNA. Fluorescent dyes allow researchers to monitor the amplification of any double-stranded DNA sequence. The ability of multiple dyes to bind to a single amplified molecule increases sensitivity for detecting amplification products. Probes are not required in this method, which reduces assay setup as well as running costs.  

Sequence-Specific DNA Probes

Sequence-specific DNA probes consist of fluorescently labeled reports. This allows for specific hybridization of the probe with its complementary DNA target. The targeted nature of probe-based qPCR results in low background and eliminates the presence of false negatives. Probes can also be labeled with different, distinguishable reporter dyes to amplify two distinct sequences in one reaction tube.