Transposons, mobile DNA elements found in the genomes of prokaryotic and eukaryotic organisms, move randomly from one site in a chromosome to another using a process catalyzed by transposases. This process, called transposition, occurs naturally but infrequently in cells as a means of genetic change. For many years scientists have used transposons for genetic research. A new system, combining Tn5 transposase and a Tn5-derived transposon to form a stable synaptic complex, forms the basis of EZ::TN Transposon Tools from Epicentre Technologies of Madison, Wis.The EZ::TN Transposon in vitro insertion kits eliminate the need for primer walking and subcloning of DNA when sequencing large plasmid and cosmid clones. The two-hour EZ::TN insertion reaction requires just 0.2 µg of plasmid or cosmid DNA to generate >106 independent sequencing templates. Each has a single randomly inserted transposon containing a selectable marker (Tetr or Kanr) and priming sites for sequencing. Individual transposon insertion ...