BAND BROADENING IN GEL-ELECTROPHORESIS - SCALING LAWS FOR THE DISPERSION COEFFICIENT MEASURED BY FRAP

We determined quantitatively the band broadening effect during gel ele ctrophoresis by measuring the longitudinal dispersion coefficient D-x, with a fluorescence recovery after photobleaching setup, coupled to a n electrophoretic cell. We carried out measurements as a function of t he electric field, the average pore size, and the molecular length of DNA fragments. Our results are in good agreement with the predictions of the biased reptation model with fluctuations described by T. A. Duk e et al. [(1992) Physics Review Letters, vol. 69, pp. 3260-3263]. This agreement is observed on single-stranded DNA [persistence length cong ruent to 4 nm; B. Tinland et al. (1997) Macromolecules, vol. 30 pp. 57 63-5765] in polyacrylamide gels and on double-stranded DNA (persistenc e length congruent to 50 nm) in agarose gels, two systems where the ra tio between the average pore size and the Kuhn length is larger than 1 . (C) 1998 John Wiley & Sons, Inc.