Method for improving the quality of genomic DNA obtained from minute quantities of tissue and blood samples using Chelex 100 resin

Utkarsha A. Singh, Mukta Kumari, Soumya Iyengar

Although genomic DNA isolation using the Chelex 100 resin is rapid and inexpensive, the DNA obtained by this method has a low concentration in solution and contains suspended impurities. The presence of debris in the DNA solution may result in degradation of DNA on long term storage and inhibition of the polymerase chain reaction. In order to remove impurities and concentrate the DNA in solution, we have introduced modifications in the existing DNA isolation protocol using Chelex-100. We used ammonium acetate to precipitate proteins and a sodium acetate- isopropanol mixture to pellet out DNA which was washed with ethanol. A pure DNA pellet that can be dissolved in water or Tris-EDTA buffer and stored for a long time at - 80 °C was obtained. We also observed a 20-fold change in the DNA concentration following precipitation and re-dissolution. Our method is different from other extraction methods since it uses non-toxic, easily available and inexpensive reagents as well as minimal amounts of blood or tissue samples for the DNA extraction process. Besides its use in sex determination and genotyping in lab animals as described in this paper, it may also have applications in forensic science and diagnostics such as the easy detection of pathogenic DNA in blood.