THE LIMITING MOBILITY OF DNA-SEQUENCING FRAGMENTS FOR BOTH CROSS-LINKED AND NONCROSS-LINKED POLYMERS IN CAPILLARY ELECTROPHORESIS - DNA-SEQUENCING AT 1200-V-CM(-1)

The mobility of DNA sequencing fragments was measured in Long-Ranger g els at an electric field ranging from 200 to 1200 V cm(-1) and in nonc ross-linked polyacrylamide at electric fields ranging from 100 to 300 V cm(-1). In both cases, N the fragment length that denotes the onset of biased reptation with orientation, is inversely proportional to el ectric field. The inverse dependence of N is inconsistent with the or iginal biased reptation model but is consistent with modern models of DNA migration. While separation speed increases dramatically with elec tric field, the number of bases determined in a separation decreases i n proportion to field strength. We present a DNA sequencing run at an electric field of 1200 V cm(-1). Roughly 200 bases of sequence are det ermined in 3.5 min.