Construction of an Overlapping YAC Library of the Arabidopsis thaliana Genome

Abstract

As part of an international effort to construct an overlapping yeast artificial chromosome (YAC) library of the Arabidopsis thaliana genome, we have been identifying and linking YAC clones that cover the top halves of chromosomes 4 and 5. All the available RFLP markers mapping to these regions were hybridised to filters carrying different YAC libraries. The YAC colonies were arrayed such that an entire library was contained on one small filter, greatly simplifying the screening procedure. The collaborative effort has currently resulted in 30% of the genome being represented in mapped YAC clones. Probes derived from the ends of the YAC inserts, using either inverse polymerase chain reaction (PCR) or left-end rescue, are now being used to walk out to link the YAC clones hybridising to adjacent RFLP markers.