EFFICIENT REMOVAL OF PCR INHIBITORS USING AGAROSE-EMBEDDED DNA PREPARATIONS

The use of agarose blocks containing embedded DNA improves the PCR amp lification from templates naturally contaminated with polysaccharides or humic acids, two powerful PCR inhibitors. Presumably, the differenc e in size between the DNA macromolecules and these contaminants allows their effective removal from the agarose blocks by diffusion during t he washing steps, whereas genomic DNA remains trapped within them. In addition, agarose-embedded DNA can be directly used for PCR since low melting point agarose does not interfere with the reaction. This simpl e and inexpensive method is also convenient for genomic DNAs extracted by other procedures, and-it is potentially useful for samples contain ing other kinds of soluble inhibitors, overcoming this important probl em of current amplification techniques.