Before (top right is positive control):
After (far right is positive control):
I am amplifying the ITS region for yeasts using the Chelex DNA extraction method. 96 samples are done in a PCR plate with the controls separately in 2 tubes (one pos one neg) with the same volume of master mix.
As you can see the positive control is working for the current gels without any streaking which I think indicates something with the DNA extraction but I have done quite a few now and I'm not sure that is the problem.
What can cause streaking on a gel which would only act on some samples and not the positive control?
I have tried to think of everything it could be but all the materials that have changed (different lots of ITS primers, new lot of loading dye, new lots of dNTP's) would all impact on the positive control as it is treated the same...
Happy to answer any further questions!
Edited by _willo_, 12 June 2010 - 10:15 PM.