The s-RT-MELT assay converts PCR fragments generated at positions of mutations by the Surveyor TM enzyme to fully amplifiable sequences that enable selective PCR amplification in a subsequent quantitative PCR detection method. Following denaturation and re-annealing of PCR products that leads to formation of cross-hybridized sequences at the positions of mutations ( Figure 1A ) the sample is exposed to Surveyor TM endonuclease that recognizes base pair mismatches or small loops with high specificity (28) and generates a break on both DNA strands 3 0 to the mismatch. The resulting DNA fragments participate in a terminal transferase (TdT) reaction that leads to polynucleotide 'tailing' (sequential addition of adenine, poly-A-tail) at the 3 0 -ends. A real-time PCR reaction is subsequently performed using adjusted conditions that enable selective amplification of the mutantonly fragments, followed by real-time melting curve analysis for identification of mutations in the presence of SYBR-GREEN TM or LC-GREEN TM DNA dye.