New experimental data are presented on the gel electrophoresis of DNA. Experiment was made for molecules of length 173 kbp, in 1 percent agarose gel, in TAE 1 \times buffer and the field intensity between 5 and 9 V/cm. The results are compared with our computer simulations, performed within the repton model of Duke and Rubinstein. The ranges of field and molecule length are determined, where the geometration effect appears. We investigate also the field dependence of the velocity and the diffusion coefficient at the border of the geometration regime.

PACS numbers: 87.15.Tt, 05.10.Ln, 83.10.Kn