AAV or adeno-associated virus is a delivery method for getting cas9 mRNA (the code that says, make cas9 protein and do gene editing). Zinc finger nucleases are

AAV or adeno-associated virus is a delivery method for getting cas9 mRNA (the code that says, make cas9 protein and do gene editing). Zinc finger nucleases are a similar class of dna editing proteins. In this specific experiment they chose to transfect cells with plasmid directly rather than transduce with virus.