Cas12a recognizes and cleaves target double-stranded DNA (dsDNA), and its collateral cleavage activity is activated, which can efficiently cleave non-specific single-stranded DNA (ssDNA). CRISPR/Cas12a can be used to detect DNA templates and amplify signals by designing DNA probes labeled with fluorescent groups or other markers at both ends. Common detection methods include real-time fluorescence and colloidal gold chromatography. GRNA specifically recognizes the target region, the CRISPR/Cas12a system is equivalent to a "secondary screening" of target DNA or DNA amplification products, so it has high specificity.