from Wittwer CT and Farrar JS (2011) in PCR Troubleshooting and Optimization

dsDNA dyes are commonplace in the molecular biology laboratory. Although ethidium bromide was first used in real-time PCR, SYBR Green I is by far the most common dye in real-time PCR today. Introduced along with the LightCycler, it is more fluorescent than ethidium bromide and is easily excited at the same wavelength as fluorescein. Most real-time PCR is performed with dsDNA dyes for reasons of cost and convenience. Any PCR can be monitored with SYBR Green I. However, because dsDNA dyes are generic, there is a risk of non-specific detection of alternative PCR products. This risk can be partly eliminated by acquiring fluorescence at a temperature where only the desired product is double-stranded. Melting analysis can also differentiate between specific and non-specific products (Wittwer and Farrar, 2011 in PCR Troubleshooting and Optimization).