A fast, efficient technique is described for the extraction of DNA from a large number of samples. The applications of this method include population genetics, plant breeding, and genetic screening. In the field, samples are collected in premeasured silica gel aliquots in polypropylene blocks, which are later used to grind the dried tissue. This permits naturalists, breeders, and collaborators to collect a large number of samples in a short amount of time and allows the samples to dry quickly during shipping. No phenol or chloroform steps are required to obtain high-quality DNA. Samples representing 12 plant families, three invertebrates, and a mammal were included. Quantities of DNA obtained were consistent with or better than other techniques. The quality of samples was tested by amplification of the internal transcribed spacer region. Test amplifications were successful, confirming the quality of extracted DNA. [ABSTRACT FROM AUTHOR]