Table 1. The optimization of the pig fibroblasts transfected with ZFNs.

ZFNs	ZFNs type	ZFNs amount	mutations
set 1	plasmid	0.5 μg	0/30 (0)
	plasmid	1 μg	2/97 (2.04%)
	plasmid	2 μg	0/32 (0)
	mRNA	2 μg	0/ 95 (0)
	plasmid	4 μg	0/98 (0)
set 2	plasmid	0.5 μg	1/96 (1.04%)
	plasmid	1 μg	3/94 (3.19%)
	plasmid	2 μg	2/66 (3.03%)
	mRNA	2 μg	0/91 (0)
	plasmid	4 μg	18/80 (22.5%)

ZFNs activities were determined by TA cloning and Sanger sequencing.