Use instead of dTTP in PCR and RT-PCR protocols to avoid carryover of previous amplifications. Substitution of dUTP for dTTP in PCR results in uracil-containing PCR products that are suitable for most standard applications. The enzyme uracil-N-glycosylase (UNG, also known as UDG) can be added to a PCR premix to remove uracil from any contaminating PCR product, thus avoiding false positives. Each batch of dUTP is tested to ensure specific DNA amplification and absence of nuclease activity.