TABLE 1.

Comparison of CRISPR/Cas9, TALENs, and ZFNs in genome editing technologies.

	CRISPR/Cas9	TALENs (transcription activator-like effector nucleases)	ZFNs (zinc finger nucleases)
Mechanism of action	Cas9 nuclease is guided to DNA loci by guide RNA	DNA is bound by TALEs, and double-strand breaks are caused by the FokI nuclease	DNA is bound by zinc finger domains, and FokI nuclease cleaves
DNA Repair Pathways	DSBs repaired using NHEJ or HDR	DSBs repaired using NHEJ or HDR	DSBs modified using NHEJ or HDR
DNA targeting strategy	RNA-based	TALE-derived DNA-binding domains	Zinc finger motifs customized for specific sequences
Applications	Gene insertion, modification, multiplexing and gene knockout	Genome editing in differenet cell types and different organisms	Precision editing
Uses	Trials involving humans, animals, plants and various therapeutic strategies	Genetic engineering	Genetic research, early genetic studies and therapeutic applications