Help with PCR

[julyduva]

Good morning,

I'm student of master and my thesis is with animals virus. I have problems with the PCR: I ruled out contamination of the reactives, but in the positive samples appear a unknown band, the negative control is negative.

Can somebody help me with papers or handbooks that talk about mistakes in PCR?

Thanks for all.

[asorbie]

Can you give us a little more information, it may be that the unknown band is due to non-specific binding of your primers? What size is it roughly? What cycling conditions did you use, composition of your master mix etc? Bio-rad PCR troubleshooting is always a good place to start: http://www.bio-rad.com/en-uk/applica...roubleshooting

[Dorota]

In your positive samples, do you see your expected band AND an unknown band or you just see unknown/unexpected band? Is it PCR that is known to produce good results or you are trying to develop a PCR ?