Strange Taqman probe negative fluorescence - (Apr/01/2016 )

Dear colleagues,

I'm observing strange behavior of my Taqman probes during the very first cycles of PCR: fluorescence becomes negative first, on later cycles things going more usual, but that first pitch spoils the whole picture. (see picture)

I’ve tried to find out what is that but failed, anyone knows anything?

Thank you a lot in advance!

I don't why this happened. When I did qPCR, it seems had similar picture, but had no influence for the last result.

The raw signal probably undergoes some technical normalization before showning in the graph, it obviously has no effect on the amplification plot so I would not worry about it. such early cycles are not even used for background normalization (or this may be actually also after background normalization, which takes zeroes the pre-amplification line).