The basic building blocks and evolution of CRISPR-CAS systems.

  title={The basic building blocks and evolution of CRISPR-CAS systems.},
  author={Kira S. Makarova and Yuri I. Wolf and Eugene V. Koonin},
  journal={Biochemical Society transactions},
  volume={41 6},
CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) is an adaptive immunity system in bacteria and archaea that functions via a distinct self/non-self recognition mechanism that involves unique spacers homologous with viral or plasmid DNA and integrated into the CRISPR loci. Most of the Cas proteins evolve under relaxed purifying selection and some underwent dramatic structural rearrangements during evolution. In many cases, CRISPR-Cas system components… CONTINUE READING