Band broadening in gel electrophoresis of DNA: Measurements of longitudinal and transverse dispersion coefficients

The experimental determination of the band broadening effect during constant gel electrophoresis of linear DNA has been carried out using the fluorescence recovery after photobleaching technique. The dependence of dispersion coefficients parallel ${(D}_x)$ and perpendicular ${(D}_y)$ to the field direction with the electric field and DNA molecular length is presented. The variation of both coefficients can be represented on master curves. Finally, values of the ratio $D_x{/D}_y$ have been found to be in good agreement with the recent development of the biased reptation model with fluctuations.