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 gels at an electric field ranging from 200 to 1200 V cm −1 and in noncross‐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 electric field. The inverse dependence of N * is inconsistent with the original biased reptation model but is consistent with modern models of DNA migration. While separation speed increases dramatically with electric field, the number of bases determined in a separation decreases in 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 determined in 3.5 min.