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  • FAQ: Why are there high molecular weight smears or DNA in the wells of an agarose gel after a PCR using Phusion® High-Fidelity DNA Polymerase?

    Strong protein binding to the DNA may be preventing proper gel separation. Try adding 1% SDS to the loading dye just before running the gel.
    Or non-specific products are being amplified. To avoid this we suggest the following:
    * Reduce polymerase concentration.
    * Shorten extension time.
    * Reduce total number of cycles.
    * Increase annealing temperature or try 2-step protocol.
    * Optimize Mg2+ concentration.
    * Lower primer concentration.