Genome editing is the precise targeted modification of the nucleotide sequence of the genome.

In the case of CRISPR/Cas9, a guide RNA takes the place of a DNA binding protein, therefore simplifying the process. CRISPR stands for “Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)”.

The CRISPR/Cas9 system is based on a bacterial defense system against foreign DNA (e.g. viruses), whereby an RNA guided nuclease makes highly targeted cuts in the genome.

The CRISPR-Cas9 complex consists of (see picture below)

  • a Cas9 protein (Cas9 stands for “CRISPR associated)
  • a single guide RNA (sgRNA)