Direct PCR from solid tissues without DNA extraction.

on the use of formamide and reduced incubation temperatures. Here we describe a modification of FoLT PCR which allows direct amplification from solid tissue samples without the need for any DNA purification steps. Two oligonucleotide primer combinations directed against the murine I82 microglobulin gene were used in this study. Using a standard PCR protocol it was not possible to amplify the appropriate DNA fragment directly from a 1 mm3 slice of murine liver tissue using a number of modifications of a standard PCR protocol, as illustrated in Figure 1. Instead of the expected amplification products of 300 bps and 460 bps respectively only DNA smears were evident. A similar result was also obtained for samples where the tissue was teased to give rise to a single cell suspension. No PCR products were observed when the standard FoLT PCR protocol was applied to solid tissue or cell suspension. Heating the samples in formamide for 10 minutes prior to amplification allowed the target DNA fragments to be amplified. However,