Table 1 Comparison of precise genome-editing strategies

HR

Point mutation, insertion, deletion; Dividing cells

High specificity

Extremely low efficiency

^40,41,49

ZFN-HDR

Point mutation, insertion, deletion; Dividing cells

High specificity

DSB dependent; Labor intensive cloning; Low efficiency

^82,83,86,87

TALEN-HDR

Point mutation, insertion, deletion; Dividing cells

High specificity

DSB dependent; Labor intensive cloning; Low efficiency

^{64,93,94,95,96}

Cas9-HDR

Point mutation, insertion, deletion; Dividing cells

Easy to engineer

DSB dependent; PAM site necessary; Off-target effects; Low efficiency

^{65,99,116,118,161}

Cre-loxP

Excision, Inversion, translocation; Dividing and non-dividing cells

High specificity; High efficiency

Not useful for insertion or correction; Need prior insertion of loxP sites

^{189,194,195,197}

HITI

Insertion; Dividing and non-dividing cells

Easy to engineer

DSB dependent; PAM site necessary; Off-target effects; Low efficiency

^69,161,200

BE

Point mutation; Dividing and non-dividing cells

High efficiency; non-dividing cells

PAM site necessary; Off-target effects; Only conversion of C•G to T•A, A•T to G•C, or C•G-to-G•C

^{25,26,161,163,206,223}

PE

Point mutation, small insertion, and deletion; Dividing and non-dividing cells

Non-dividing cells

PAM site necessary; off-target effects; low efficiency; limited to small edits.

^27,247

CAST

Large DNA insertion

Large DNA insertions

Low efficiency

^77,78