Practice question

SYBR Green I is a sensitive double-stranded DNA intercalating dye widely used in real-time PCR. In free solution its fluorescence is minimal, but upon binding to minor groove and intercalation between base pairs of duplex DNA, conformational restriction greatly enhances quantum yield, producing strong green emission under excitation. Signal intensity increases proportionally with amplicon accumulation, allowing quantification without sequence-specific probes. It does not block nonspecific amplification, cleave DNA or quench fluorescence; rather, it serves as reporter of total double-stranded product. Specificity must be confirmed by melt curve analysis since any duplex, including dimers, will fluoresce.