Schematic of a TALEN and its flanking sequence. a) An exon with TALEN binding site. The short flanking sequences are needed for processing TAL sites that are near the ends of an exon or for very short exons. The long flanking sequence is used to find enzymes that cut within the amplicon. Binding sites may be defined with a prefix or a postfix. If restriction fragment length polymorphism (RFLP) is used to measure the effect of TALENs, the uniqueness of the enzyme recognition site is found on the span including both long flanking sequences. b) Test sequence designed with only one TALEN site. The prefix thymines are indicated with minuscules. The recognition site for the restriction enzyme is in boldface.