Molecular beacons: colorful analysis of nucleic acids

The completion of the Humane Genome Project has resulted in an exponential rise in the demand for molecular diagnostic assays. To meet this demand, several innovative technologies have become available for performing homogeneous genetic analyses. For this type of assay, special detector probes are necessary. In 1996, Tyagi and Kramer described fluorogenic hairpin-shaped detector probes, called 'molecular beacons', which are extraordinarily specific. Since they characterize alleles by the generation of fluorescent signals, they are perfectly suited for homogeneous genetic analysis. Molecular beacons assays are simple, fast, inexpensive, sensitive, utilize a high-throughput format, enable the testing of many samples simultaneously and allow the detection of a series of different agents in the same assay tube. This review is designed to give the reader a greater understanding of the exciting applications of molecular beacons in DNA, RNA and protein studies.