MEASUREMENT OF DIFFUSION-COEFFICIENTS OF DNA IN AGAROSE-GEL

Diffusion coefficients of three linearized plasmid DNAs, sizes from 2686 to 5996 base pairs, have been measured in 0.5% agarose gel. Diffusion of these DNAs in the gel is about 3 times slower than in free solution. The diffusion coefficients vary as the reciprocal of the molecular weight, indicating that these DNAs are moving through the gel by a mechanism intermediate between free diffusion and reptation. This is in accord with the electrophoretic mobility reported in the literature for DNA samples of similar size in agarose.