Apparently we need to be aware of this.
Clustered regularly interspaced short palindromic repeats (CRISPR, pronounced crisper) are segments of prokaryotic DNA containing short repetitions of base sequences. Each repetition is followed by short segments of “spacer DNA” from previous exposures to a bacteriophage virus or plasmid.
The CRISPR/Cas system is a prokaryotic immune systemthat confers resistance to foreign genetic elements such as those present within plasmids and phages, and provides a form of acquired immunity. CRISPR associated proteins (Cas) use the CRISPR spacers to recognize and cut these exogenous genetic elements in a manner analogous to RNA interference in eukaryotic organisms.CRISPRs are found in approximately 40% of sequenced bacterial genomes and 90% of sequenced archaea.[note 1]