qPCR negative controls

[Bas Jansen]

In article <58gkigF2gt9jnU1 from mid.individual.net>,
 "Peter Ellis" <pjie2 from cam.ac.uk> wrote:

> Gerardine.Persson from gmail.com wrote:
> >
> > My questions:
> > - What exactly is actually amplified here? I've had many students ask
> > me, and I grow tired of answering "I don't know, stop asking"
> 
> It'll vary from lab to lab depending on the source of the contamination.  It 
> could be carry-over from your actual samples (and the CT will vary depending 
> on the amount of carry-over), or it could just be primer dimer, in which 
> case a melt curve will show you that it's a different amplicon from the one 
> found in wells with template.

Good advice. In addition, you may just want to look at the amplification 
plots for your negative controls. If they are way flatter than the usual 
positive controls, it is, in my experience at least, some byproduct, 
usually primer multimers. I have also noticed in our lab that people put 
the threshold too low...

Bas