cDNA and additional bands when run on gel - I get a band o fthe same Mw regardless of the primers I use (Oct/18/2008 )

Hmmmm. Just wondering. I have synthesised cDNA from an insect larva and then used it as template for PCR with various primers for different sequences. When I run the PCR products on an agarose gel I get the usual bands of my desired amplicons plus some that seem non specific priming. However there is always a band present in every single lane regardless of the primers I use.It rub at about ~800 bp. I thought it could be rRNA contamination but I have treated my cDNA with an RNase. Any ideas?

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That's weird. Do you have RT- control and negative (water) control? RNase treatment not complete?

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I have the controls that came with the kit (Invitrogen) but the positive didn't work. Since my amplicons were ok i didn't pay much attention to it.

The RNase treatment went for a while. I had 5 micrograms of template (RNA) to begin with, maybe it was too much?

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