Figure 1.

Lox site spacer and repeat variants. (a) LoxP site organization. Inverted repeats (rectangles) separated by spacer (triangle). (b) Lox inverted repeat variants. Red bar indicates location of divergence from LoxP. Right of the diagram are the name of the variant and the corresponding sequence. Variant specific sequence indicated in red in lower case. (c) Lox spacer variants. Spacer variant name and sequence indicated at right of diagram. Sequence variations from LoxP indicated in lower case in color of the spacer of the corresponding diagram.