Capillary electrophoresis of supercoiled and linear DNA in dilute hydroxyethyl cellulose solution

Capillary electrophoresis in dilute hydroxyethyl cellulose is shown to separate supercoiled DNA in the size range 2000-16 000 base pairs. The plasmids migrate more slowly than linear ds-DNA of the same sizes. Plasmid bandwidths are larger than observed for ds-DNA, allowing identification of the type of DNA by bandwidth. The differing dependence of mobility on chain length can be explained by assuming that a plasmid migrates as an elastic rod, while ds-DNA migrates as a wormlike chain.