Pulsed field agarose gel electrophoresis in the study of morphogenesis: Packaging of double‐stranded DNA in the capsids of bacteriophages

To understand how comparatively simple macromolecular components become biological systems, studies are made of the morphogenesis of bacteriophages. Pulsed field agarose gel electrophoresis (PFGE) has contributed to these studies by: (i) improving the length resolution of both mature, linear, double‐stranded bacteriophage DNAs and the concatemers formed both in vivo and in vitro by the end‐to‐end joining of these mature bacteriophage DNAs, (ii) improving the resolution of circular conformers of bacteriophage DNAs, (iii) improving the resolution of linear single‐stranded bacteriophage DNAs, (iv) providing a comparatively simple technique for analyzing protein‐DNA complexes, and (v) providing a solid‐phase quantitative assay for all forms of bacteriophage DNA; solid‐phase assays are both less complex and more efficient than liquid‐phase assays such as rate zonal centrifugation. Conversely, studies of bacteriophages have contributed to PFGE the DNA standards used for determining the length of nonbacteriophage DNAs. Among the solid‐phase assays based on PFGE is an assay for excluded volume effects.