How does Crispr/Cas9 work?

1. identify the sequence that has to be edited in the genome. 2. create a guide RNA that is complementary to the target sequence. 3. attach the guide RNA to Cas9 (a DNA cutting enzyme). 4. introduce the complex into the target cells. 5. the complex will recognise the target sequence and cut the DNA. 6. the cell will try and repair these breaks by non homologous endjoining. 7. NHEJ often makes mistakes, when these are not removed, the gene is knocked out. 8. when you want to create a knock in, you have to include a donor sequence that is complementary to the target site, except for the mutation that you want to introduce. for this process the repair mechanism of homologous recombination is needed.