Abstract: A detection system for enriching a low-abundance single-nucleotide mutant gene on the basis of nuclease-coupled PCR principle. Also provided is a method for increasing relative abundance of a target nucleic acid, comprising: (a) providing a nucleic acid sample containing the target nucleic acid and a non-target nucleic acid, the target nucleic acid having abundance of F1a in the nucleic acid sample; and (b) performing PCR and a nucleic acid cleavage reaction in an amplification-cleavage reaction system using the nucleic acids in the nucleic acid sample as templates to obtain an amplification-cleavage reaction product, the target nucleic acid having abundance of F1b in the amplification-cleavage reaction product, and the ratio of F1b/F1a being ?10.

Abstract: Provided are a method for detecting a nucleic acid based on prokaryotic Argonaute protein and an application thereof. In particular, provided is a system for detecting a target nucleic acid molecule. The system comprises guide ssDNA, a gene-editing enzyme Pyrococcus furiosus Argonaute (PfAgo), and a fluorescent reporter nucleic acid.