Tandem PCR: a novel and efficient unit amplification model for the preparation of small DNA fragments.

The present DNA marker preparation with PCR amplification, one primer pair for one target DNA fragment, was very tedious and labor intensive. To develop a simple and efficient system for the preparation of small DNA fragments, a novel PCR amplification pattern was designed and tested, of which targeted small DNA fragments were amplified in groups as a unit with a specific synthetic vector as template DNA. The amplified units can be different dependent on the identities of the employed primers and give out variable combinations of small DNA fragments through complete or partial restrictive digestion with EcoRI. The novel pattern made the PCR amplification of small DNA fragments not only more efficient but also more economic than ever before. The tandem PCR pattern, as the most efficient and high throughput method for small DNA fragment preparation, has wide application for the production of various DNA markers and a good complementation to the larger DNA fragment preparation by complex synthetic vector fermentation.