Shown by Bat1-FokI was 35 cleavage (11 bp spacer) while dTALEBat1mimic -FokI had a maximum efficacy of 86 cleavage (19 bp spacer; Figure 4). That dTALEBat1mimic -FokI showed greater flexibility with respect to spacer length may relate to the previously optimized architecture employed (18). TALEN architecture is known to play a decisive role in spacer preference (23). Similarly, alternative Bat1