. Author manuscript; available in PMC: 2017 Dec 1.

Published in final edited form as: Am J Med Genet C Semin Med Genet. 2016 Oct 28;172(4):332–348. doi: 10.1002/ajmg.c.31529

Table 1.

Key features of the major classes of programmable nucleases

	Meganucleases	ZFNs	TALENs	CRISPR/Cas
Nuclease	Homing endonucleases	FokI	FokI	Cas9
Type of recognition	Protein-DNA	Protein-DNA	Protein-DNA	RNA-DNA
Recognition site length	14–40 bp	18–36 bp	30–40 bp	~20 bp
Engineering complexity	high	high	moderate	low
Off-target effects	low	high	low	variable
Size	~1 kb	~1 kb/ monomer	~3 kb/ monomer	~3.3 kb – ~4.2 kb