Hey,

so it has happened a couple of times by now that I extracted RNA (RNA protect bacterial reagent, Qiagen) and DNase treated it with on column digestion using DNase I and a second DNase treatment step using TURBO DNase (2 µl, 30 min). When running the freshly treated samples through PCR and then on a gel there was no band. However, when using the RNA for cDNA synthesis and then checking it again with the same primers as control, there suddenly appears a band in the RNA as well, though it was pure before. All that I did with it in between these instances was freeze it at -80 °C. I make very sure I don't contaminate anything, but it has been an reoccurring issue.

Any ideas as to why this keeps happening?