No abstract

The number of bases that can be read in a single run by a DNA sequencing instrument that detects fluorophore labeled DNA arriving at a "finsh-lineyy located a fmed distance from the starting wells is influenced by numerous parameters. Strategies for improving the length-of-read of a DNA sequencer can be based on quantitative models of the separation of DNA by gel electrophoresis. The dispersion function of the electrophoretic system -the relationship between molecular contour length and time of anival at the detector -is useful in characterizing the performance of a DNA sequencer, We adapted analytical representations of dispersion functions, originally developed for slapshot imaging of DNA gels, (samples electrophoresed for constant time), to finish-line imaging, and demonstrated that a logistic-type function with non-integral exponent is required to descriie the experimental data. We use this dispersion function to determine the resolution length and resolving power of a LI-COR DNA sequencing system and a custom built capillary gel electrophoresis system, and discuss the factors that presently limit the number of bases that can be determined reliably in a single sequencing run.