Purification and Concentration of Nucleic Acids

The purification and concentration of nucleic acids have become routine procedures in most biology and molecular biology laboratories. This unit covers the basic principles and procedures for the isolation, purification, and manipulation of solutions of DNA or RNA. The basic DNA protocol, using phenol extraction and ethanol precipitation, is appropriate for the purification of DNA from small volumes (<0.4 ml) at concentrations ≤1 mg/ml. Purification of DNA using commercially available silica membrane spin columns is presented as an alternate protocol. Isolation and purification of RNA from mammalian cells or tissues is also examined. Use of the protein denaturant guanidine thiocyanate and water-saturated phenol, followed by concentration by isopropanol precipitation, for producing small samples of RNA is illustrated in the basic RNA protocol.