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  • FAQ: Why is the product a smear when visualized on an agarose gel?

    Taq DNA Polymerase has a half-life of 45 minutes at 94°C, therefore conditions for making long products (>5kb) can degrade the polymerase. In this case, increasing the amount of Taq DNA Polymerase in the reaction can help. Vent DNA Polymerase (NEB# M0254) and Deep Vent DNA Polymerase (NEB# M0258) are more thermostable polymerases. Q5® High-Fidelity DNA Polymerase (NEB# M0491), Q5 Hot Start High-Fidelity DNA Polymerase (NEB# M0493), Phusion® High-Fidelity DNA Polymerase (NEB# M0530), and Phusion Hot Start Flex DNA Polymerase (NEB# M0535) amplify targets up to 20 kb with extremely high fidelity.  LongAmp® Taq DNA Polymerase (NEB# M0323), Crimson LongAmp Taq DNA Polymerase (NEB# M0326), and LongAmp Hot Start Taq DNA Polymerase (NEB# M0534) can amplify targets up to 30 kb in length.