M. Harry et al., Evaluation of purification procedures for DNA extracted from organic rich samples: Interference with humic substances, ANALUSIS, 27(5), 1999, pp. 439-442
A limitation of the use of the Polymerase Chain Reaction (PCR) for soil DNA
analysis is the contamination by humic substances. Numerous studies have b
een devoted to the elaboration of an effective purification method but none
appears universal. During our investigations of soil bacterial changes ind
uced by soil-feeding termites, we found that humic acid content usually imp
ede DNA purification. Indeed, humic acids and nucleic acids share similar p
hysicochemical properties. Here, we tested eight purification procedures in
cluding electrophoretical and chromatographical methods. The results show f
or DNA extracted from humic rich samples, e.g. termite mounds, that only th
e combination of two methods gave a DNA sufficiently pure to perform succes
sful amplifications.