Quantification of DNA

Abstract

Quantification of DNA is a very important step in many procedures where it is necessary to know the amount of DNA that is present when carrying out restriction digests or performing different techniques such as PCR and RAPDs. There are several methods for quantifying DNA, the most widespread being: (i) the comparison of an aliquot of the extracted sample with standard DNAs of known concentration using gel electrophoresis and (ii) spectrophotometric determination. With both methods additional information is gained concerning the quality and purity of the extracted sample obtained. Normally both methods are used, but if the amount of DNA available is very small the gel electrophoresis technique alone may be employed. If there is no limitation on DNA amount, however, spectrophotometric measures should also be taken.