CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) and associated Cas proteins comprise a system for heritable host defense by prokaryotic cells against phage and other foreign DNA; HD-like nuclease, specifically digesting double-stranded oligonucleotides and preferably cleaving at G:C pairs; signature gene for Type I
Jiyao W et al.(2023). "The conserved domain database in 2023.",