Sequencing and Distribution Analysis of Dissociation Transposon Events Throughout the Zea Mays Genome

The transposon Dissociation is a nonautonomous element derived from Activator. The Ac/Ds project, a collaborative effort to cast stable Ds insertions throughout the maize genome, is a valuable tool for generating a reverse genetics resource. By using Ac::immobilized, an Ac element that cannot mobilize but can produce transposase, a Ds element in the anthocyanin regulating allele r1-sc:m3 can be mobilized. As of October 5th, 2007, 816 unlinked and 126 linked families have been produced and sequenced, with a 77% success rate. Repeat masking shows a low content of repetitive sequence, implying that these events in genic regions. By examining transposition events into the donor chromosome, transposition patterns can be observed. 95% of hits land within 40 cM of the donor site. Because the Ac/Ds project uses the W22 inbred line, sequence from large fDs fragments was compared against GSS assemblies from B73. The identity between B73 and W22 is 96.5%.