CRISPR is an array of clustered regularly interspaced short palindromic repeats,and plays an active role in regulating foreign invasive elements in the prokaryotic genomes.Recently CRISPR has been engineered as a genomic editing tool to conduct a target-specific gene editing in the mammalian genomes.CRISPR-associated gene (Cas) encodes an enzyme to facilitate the editing machinery,and the most well-studied system is the CRISPR-Cas9 pair.We carried out a comprehensive curation of the existing annotation of CRISPRs in the prokaryotic genomes,and observed quite a number of inconsistency in the annotations.The observed results demonstrated that its essential to sensitively detect the direct repeats (DRs)for a CRISPR detection program.The comparison with the existing tools also supports this suggestion[1].