Molecular beacons are hair-pin shaped oligonucleotides containing a fluorophore on one end and a quenching dye on the opposite end. Under conditions that prevent the oligonucleotide from hybridizing to its complementary target, the fluorescent and quenching dye are proximal to one another, thus preventing fluorescence resonance energy transfer (FRET). Once hybridization occurs, the loop structure is converted to a more rigid conformation causing separation of the fluorophore and quencher leading to fluorescence. For quantitative PCR, molecular beacons bind to the amplified target following each cycle of amplification and the resulting signal is proportional to the amount of template. As with other real time PCR formats, the specific reaction conditions must be optimized for each primer/probe set to ensure accuracy and precision. This page provides a link to primer/probe sets that have been synthesized, tested and optimized for the measurement of gene expression in the organisms listed below.