Myeloid Leukemia

42 Picard, Silvy, and Gabert
Fig. 9. Specific fragment detection with scorpion primers. (A) Structure of a scorpion
primer: in the hairpin loop structure, the reporter (circle) and the quencher (pentagon)
are in close proximity, and the signal from the reporter dye at the 5� end of the
probe is quenched. The hairpin loop is linked to the 5� end of a specific primer (dotted
line). (B) During polymerase chain reaction (PCR), the scorpion primers are extended
to become part of the amplicon. After extension of the primer during PCR amplification,
the specific probe is able to bind to its complement within the same strand of
DNA. This hybridization event opens the hairpin loop so that fluorescence is no longer
quenched, and increases in signal are observed.