An Accurate Method for Estimating Sizes of Small and Large Plasmids and DNA Fragments by Gel Electrophoresis

Abstract
Several regression methods were tested for estimating the sizes of a wide range of plasmids (1.37-312 MDa) and restriction fragments (2.2-14.2 MDa) by agarose gel electrophoresis. The most accurate and least variable method was the multiple regression of log10 molecular size against log10 relative mobility and the reciprocal square root of the relative mobility. This method gave a good fit to all the data with low percentages errors of the molecular size estimates (.ltoreq. 3.0 .+-. 1.5%). It is suggested this method the molecular size of unknown plasmids can be accurately estimated using the Escherichai coli V517 and E. coli IR713 as standards.