Quantitative PCR (qPCR)

Definition

Quantitative PCR (qPCR) is a molecular biology technique used to amplify and simultaneously quantify a targeted DNA molecule. It enables the detection and measurement of specific genetic material in real time.

5 Must Know Facts For Your Next Test

1. qPCR uses fluorescent dyes or probes to measure the quantity of DNA during the amplification process.
2. It is highly sensitive and can detect low levels of DNA, making it useful for diagnostics and research.
3. The Ct value (cycle threshold) in qPCR indicates the cycle number at which the fluorescence exceeds a defined threshold, correlating with the amount of target DNA.
4. qPCR can be performed using either SYBR Green or TaqMan probes; SYBR Green binds to any double-stranded DNA while TaqMan probes are sequence-specific.
5. It is commonly used in gene expression analysis, pathogen detection, and genotyping.

Review Questions

• What does the Ct value indicate in qPCR?
• What are two types of fluorescent chemistries used in qPCR?
• How does qPCR differ from traditional PCR?

Related terms

Polymerase Chain Reaction (PCR):

A technique used to amplify small segments of DNA.

Reverse Transcription PCR (RT-PCR): A variation of PCR that involves converting RNA into complementary DNA (cDNA) before amplification.

Fluorescent Probe: A molecule that emits fluorescence and binds specifically to a target sequence, used for detecting specific nucleic acids in qPCR.