SYBR

SYBR refers to a family of fluorescent dyes used to detect nucleic acids in molecular biology experiments. The most widely used members are SYBR Green I, SYBR Safe, and SYBR Green II. SYBR Green I was developed by Molecular Probes (later Thermo Fisher) and binds preferentially to double-stranded DNA; when bound, the dye emits bright fluorescence under blue light excitation and green emission. SYBR Safe is a marketed alternative designed to be less mutagenic than ethidium bromide while providing similar dsDNA staining. SYBR Green II is used mainly for RNA staining in gels and other RNA detection applications.

In practice, SYBR dyes enable two main workflows: conventional gel electrophoresis, where stained DNA bands appear under UV or blue-light illumination, and real-time quantitative PCR (qPCR), where fluorescence increases as PCR products accumulate, allowing monitoring of amplification in real time. Although highly sensitive, SYBR dyes are non-specific and bind to any double-stranded DNA, including primer-dimers and non-target products, so melt-curve analysis or additional verification is often recommended to assess specificity.

Safety and handling considerations vary by product. SYBR Safe is marketed as a safer alternative to ethidium bromide, but all SYBR dyes should be handled with standard laboratory precautions and disposed of according to local regulations. They are compatible with common gel documentation systems and qPCR instruments.

History and usage context: SYBR dyes emerged in the 1990s from Molecular Probes and have since become standard tools in molecular biology for DNA visualization and real-time analysis, offering a convenient, relatively sensitive means to monitor nucleic acids without the use of radioactive labels. See also ethidium bromide and qPCR.