Artifacts in early cycles - QPCR Troubleshooting (Sep/03/2008 )

I have an issue with early artifacts appearing in the first 7 cycles of my QPCR. This is a standard protocol that is frequently used in this lab. I also get the same pattern when I use a similar protocol (different primers/probe) and the same samples. This leads me to believe that the issue lies within the sample and not the primers and probe. The sample is DNA from a pure culture so there should be no issues with environmental contamination.

This is the first time I get results like this.

Any suggestions as to what causes these half rainbows in the initial cycles. This could give me some clues as to what my problem might be.

I have attached the Amplification view in log scale.

[attachment=5244:sample1.bmp]

Thanks.

-RatRace2000-

QUOTE (RatRace2000 @ Sep 3 2008, 05:30 PM)

These artefacts are due to your chemistry (probe, enzyme, and buffer) and is your background, they only show up in log view, not in linear view.
These first cycles 1-6 (up to 10) determine your treshold lower limit. In your case not so bad, but could be better.
Just set your treshold above the top of these lines

In the beginning your chemistry reacts a bit different, wich gives such strainges results

-hebus-