Single-step direct PCR amplification from solid tissues

Conventional polymerase chain reaction (PCR) involves purifica-tion of template DNA before amplification (1). Not only is this costly and time consuming, but there is the ever present danger of cross contamination during the DNA isolation step, especially when handling large numbers of samples. Also, when conventional DNA purification methods are applied to small samples, for example clinical biopsies, there is a potential risk that valuable samples could be lost during isolation. Such problems are minimized if DNA can be amplified directly from tissue. A previous report on direct PCR amplification from solid tissues was based on the use of formamide to lyse the cells and required pre-cycling prior to PCR amplification and lower PCR temperatures (2). Here we describe a single-step method for PCR amplification of DNA directly from solid tissues, without having to pause the reaction to add the thermostable DNA polymerase after th