3′-Digoxigenin (DIG) labeled DNA hairpins (DH) (34.4 nM) were incubated with a 1000- or 500-fold excess of pre-annealed Invader probes X1:X2 or X9:X10 in HEPES buffer (50 mM HEPES, 100 mM NaCl, 5 mM MgCl2, pH 7.2, 10% sucrose, 1.44 mM spermine tetrahydrochloride) for 17 h at room temperature. RC = recognition complex. Sequence differences at the 6- or 8-position are highlighted in red. Sequences for Invader probes are X1: 5′-GGUATATATAGGC, X2: 3′-CCAUATATATCCG, X9: 5′-GGUAUATATAGGC, and X10: 3′-CCAUAUATATCCG. Adapted from reference 54 with permission from the Royal Society of Chemistry.