ABSTRACT
Nondenaturing agarose gels are the most widespread and versatile gel electrophoretic techniques for the analysis of nucleic acids. Frequently electrophoretic separations generate PCR products or restriction enzyme fragments whose lengths need to be estimated with some precision. Molecular biology is frequently conducted with circular double-stranded DNA molecules in the form of bacterial plasmids. A double-stranded DNA circular plasmid can be converted into a linear fragment with a single restriction enzyme cut. It is important to realize that a circular or linear conformation, although there is the same mass of DNA, can have profound effects on mobility in an agarose matrix. DNA molecules are separated on gels and transferred to membranes to enable nucleic acid–nucleic acid hybridization to take place between the immobilized target molecule and the probe in solution, for example in a Southern blot procedure.
