1
An RNA molecule, attached to a protein called CAS9, is programmed to match a section of DNA near the point mutation
RNA molecule
Cas9
G
C
T
A
A
Targeted ‘A’ and ‘T’ bases
T
DNA sequence
2
The RNA aligns with the DNA and the system unwinds the double helix. An enzyme within the Crispr-Cas9 tool chemically changes the 'A' to inosine – a molecule that is read as a 'G'
Cas9
‘G’
DNA sequence is ‘unwound’
and A is changed to ‘G’
T
3
The opposing strand of DNA is then nicked, instigating a repair. Upon seeing the inosine, enzymes replace the offending ‘T’ with a ‘C’
‘G’
‘T’ becomes ‘C’ correcting the mutation
C
DNA is nicked
Cas9
RNA
molecule
G
C
T
A
1
An RNA molecule, attached to a protein called CAS9, is programmed to match a section of DNA near the point mutation
A
Targeted ‘A’ and ‘T’ bases
T
DNA sequence
2
The RNA aligns with the DNA and the system unwinds the double helix. An enzyme within the Crispr-Cas9 tool chemically changes the 'A' to inosine – a molecule that is read as a 'G'
Cas9
‘G’
DNA sequence is ‘unwound’
and A is changed to ‘G’
T
3
The opposing strand of DNA is then nicked, instigating a repair. Upon seeing the inosine, enzymes replace the offending ‘T’ with a ‘C’
‘G’
‘T’ becomes ‘C’ correcting the mutation
C
DNA is nicked