Here are some recommendations:
- Primers: Ensure that your primers are designed to amplify the converted template. We recommend primers that are 24-32 nts in length and contain no more than 2-3 mixed bases (for base-pairing to C or T residues). The 3' end of your primer should not contain a mixed base or end in a residue whose conversion state is unknown.
- Polymerase: We recommend using a hot-start Taq polymerase such as Platinum Taq DNA Polymerase, Platinum Taq High Fidelity, or AccuPrime Taq DNA Polymerase. Proof-reading polymerases are not recommended because they cannot read through uracil present in DNA templates.
- Amplicon size: Bisulfite modification is harsh and may cause strand breaks. Most research publications recommend 200 bp lengths. Larger amplicons can be generated, but this requires an optimized protocol.
- Template DNA: We recommend using 2-4 µl of eluted DNA for each PCR reaction. Ensure that total template DNA is less than 500 ng.