Figure 1.

Principle of quantitative PCR. This figure was drawn using Figdraw software online (https://www.figdraw.com/static/index.html). The qPCR amplification system contained a pair of primers and a specific fluorescent probe, which labeled with a reporter fluorophore and a quenched fluorophore at each end. When the probe is intact, the fluorescence signal emitted by the reporter group is absorbed by the quenched group. When PCR amplification is performed, the probe is digested and degraded by the Taq enzyme so that the reporter and quenched groups are separated, and the reporter group gives a fluorescent signal.