Sybr Green real time pcr limit of detection - (Jul/27/2008 )

This may be a stupid question.. but

Can anyone tell me how few copies of DNA Sybr Green can reliably detect? I am getting mixed information off the internet, some saying it should be used only where there are 1000s of molecules present in a reaction.

Thanks

This depends on your assay in combination with your master mix and real-time pcr machine.
However, with a optimized assay-system you can detect a few copies (1-10 c/rxn) or a few hundreds with a higher reproducibility. If you want to detect / quantify less than 10 (or 100) copies you have to multiply your replicates (do at least 5-10). However, this is only possible if you really have optimized your assay and if you use a high-quality qpcr-machine and high-quality master mix from one of the two market leaders (Roche and ABI).
I can recommend you the FastStart Universal Sybr Master (Rox) which works on most of the qPCR-machines (not only ABI) or a LightCycler master if you work with a Roche lightcycler machine.