Porteous, L. Arlene, Ramon J. Seidler, and Lidia S. Watrud. 1997. An improved method for purifying DNA from soil for polymerase chain reaction amplification and molecular ecology applications. Molecular Ecology 6:787-791.
Current molecular biological technology provides unique opportunities to detect and identify diverse microbial populations in soils using methods based on microbial DNA rather than culturing methods since about 1% of soil microbes are believed to be culturable. In our laboratory we have developed and used a variety of newer molecular methods to directly extract and purify DNA from soil to study changes in microbial populations due to soil type, composition or location. However, our research has frequently been limited by the amount, quality, and purity of DNA that is extracted and used in subsequent analysis such as amplification using polymerase chain reaction (PCR) method. Therefore the research presented in this manuscript describes an improved method we developed to extract and purify DNA from soil to increase our test sensitivity. DNA from different soil types was amplified by the PCR method and then restricted by restriction enzyme analysis to produce a series of DNA fragments referred to as a DNA fingerprint. Using this DNA fingerprint method, we showed characteristic differences in microbial populations a from different soil systems. We anticipate these methods will also be useful in being able to show differences in microbial populations due to biological or chemical pollutants that may stress agricultural, industrial or natural soil systems.