The genetic toggle switch designed and built by Gardner, Cantor and Collins, drawn using SBOL Visual. This synthetic circuit combines two repressor motifs, as discussed in the main text. P1/P2, promoters; r1/r2, genes encoding repressor proteins; R1/R2, repressor proteins; P2 drives expression of r1 and also gfp, the latter of which is translated into GFP, the system read-out. Both repressor motifs reside on opposing strands of the same double-stranded DNA plasmid, but they have been drawn here separately for clarity.