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. Author manuscript; available in PMC: 2015 Jan 21.
Published in final edited form as: Curr Protoc Hum Genet. 2014 Jan 21;80:7.21.1–7.21.8. doi: 10.1002/0471142905.hg0721s80

Figure 1.

Figure 1

TaqMan probe versus SYBR Green for qPCR assay. (A). An oligonucleotide probe contains a reporter fluorescent dye on the 5′ end and a quencher dye on the 3′ end. Primers are designed for PCR amplification. The probe anneals with target sequence from one of the primer sites and is cleaved by the 5′ nuclease activity of Taq DNA polymerase as this primer is extended. Cleavage of the probe separates the reporter dye from the quencher dye, increasing the reporter dye signal. Cleavage of the probe removes the probe from the target strand, allowing primer extension to continue to the end of the template strand. There is an increase in fluorescence intensity proportional to the amount of amplicon produced during each PCR cycle. (B). SYBR Green dye detects PCR products by binding to double-stranded DNA formed during PCR reaction. As the PCR progresses, more PCR product is created. SYBR® dye binds to all double-stranded DNA, resulting in an increase in fluorescence intensity proportioned to the amount of PCR product produced.