SYBR Green I has been used in qPCR since the introduction of the LightCycler in 1997. However, when SYBR Green I is used for melting, it does not detect multiple products or heteroduplexes well.
With SYBR Green, low melting products are minimized or eliminated in deference to higher melting products. SYBR Green may not even detect the heteroduplexes that are characteristic of heterozygotes in variant scanning, while other dyes can to varying degrees. SYBR Green can be used for genotyping, but its inability to detect heterozygotes lowers the detection sensitivity and the amplicon size that can be analyzed. Dye heterozygote detection is correlated to their ability to saturate DNA fluorescence while not affecting PCR efficiency or quantification cycle (Cq).
These dyes are now known as "saturation dyes". Although many are now available, LCGreen (specifically developed for high resolution melting) detects heteroduplexes better than other saturation dyes (
Wittwer et al. 2024).
