High-throughput plasmid purification for capillary sequencing

The need for expeditious and inexpensive methods for high-throughput DNA se quencing has been highlighted by the accelerated pace of genome DNA sequenc ing over the past year. At the joint Genome Institute, the throughput in te rms of high-quality bases per day has increased over 20-fold during the pas t 18 mo, reaching an average of 18.3 million Phred 20 bases per day. To sup port this unprecedented scaleup, we developed an inexpensive automated meth od for the isolation and purification of double-stranded plasmid DNA clones for sequencing that is tailored to meet the more stringent needs of the ne wer capillary electrophoresis DNA sequencing machines. The protocol is base d on the magnetic bead method of solid phase reversible immobilization that has been automated by using a CRS-based robotic system. The method describ ed here has enabled us to meet our increases in production while reducing l abor and materials costs significantly.