SYBR? Green I is an asymmetrical cyanine dye, which is used to detect nucleic acids. It consists of a N-alkylated benzothiazolium or benzoxazolium ring system, that is joined by a monomethine bridge to a pyridinium or quinolinium ring system. SYBR Green I binds to the minor groove of dsDNA and is excited at a wavelength of 480 nm. It has a peak fluorescence emission of 520 nm.