Rapid method for fluorometric quantification of DNA in soil

We present a new method for the quantification of DNA in soil. This method is based on a fluorescent dye, PicoGreen (Molecular Probes), that binds specifically to double-stranded DNA. The DNA–PicoGreen complex is quantified in a fluorometer. Using this approach DNA concentrations from 25 pg ml−1 to 1 μg ml−1 may be quantified. The high sensitivity of the method allows impurities in the sample to be diluted, thereby eliminating quenching of the fluorescence. It is therefore possible to measure crude DNA extracted directly from soil without any prior purification. The method thereby enables the monitoring of the DNA yield through the different steps involved in its extraction from soil samples.