I performed colony-PCR mapping reactions to localize the Entranceposon insertions generated using the TGS Kit and analyzed the amplification products using agarose gel electrophoresis. The PCR product seemed to be a smear rather than an intact band. How do I avoid this problem?
Make sure not to use too much bacteria as a reaction template. Dilute the colony in 50-100 µL water or 0.9% saline and use 1 µL of the dilution per 20 µL PCR reaction. The excess of the E. coli genomic DNA in the PCR reaction typically results in a smeared amplification product. If you use a DNA polymerase from another manufacturer it is likely that the reaction conditions given in the TGS Kit Instruction Manual for the DyNAzyme EXT DNA Polymerase have to be modified.