Hybrid PCR sequencing: sequencing of PCR products using a universal primer

We describe a general method for making template DNA for sequencing of PCR products. The procedure may be particularly useful for PCR products where minimal sequence information is known or as an alternative to primer walking when sequencing long PCR products. A cassette containing the hybridization site for the M13 sequencing primer is ligated to a sample PCR product. Using one phosphorylated primer specific for the cassette together with one primer specific for the sample PCR product, subsequent PCR amplifies one hybrid construct directionally. This allows utilization of the universal M13 primer when sequencing of one strand after the removal of the complementary strand using lambda-exonuclease.