General guidelines for long-PCR conditions and enzyme mixtures. Efficient long-PCR results from the use of two polymerases: a non-proofreading polymerase is the main polymerase in the reaction, and a proofreading polymerase (3' to 5' exo) is present at a lower concentration. Includes: For PCR with low-complexity templates (e.g., plasmid and cosmid inserts); For PCR with moderate-complexity templates (e.g., bacterial genomic DNA); For PCR with high-complexity templates (e.g., human genomic DNA). - [Read Long-PCR Reagents and Guidelines]