Arabidopsis YAC restriction mapping. 
The approach of partial restriction mapping and vector hybridisation has been used to restriction map and align six yeast artificial chromosomes (YACs) corresponding to the top arm (approximately 27.9 centiMorgans, cM) of Arabidopsis chromosome 5 and confirm the chimeric nature of a further four clones which map to this region.  The restriction endonucleases Sma1 and Sfi1 which recognise rare-medium frequency sites in the Arabidopsis genome were used.  This work has restriction mapped a 315 kb region that includes a number of genes implicated in floral development, namely PISTILLATA and TOUSLED, and a number of uncharacterized genes involved in male gametogenesis (e.g., Ms1 and Ms37).  The information generated can be used to transcriptionally map genes to this contig and will provide data for the isolation of several uncharacterized floral development genes which lie in this region.  This approach has demonstrated how large tracts of YAC DNA can be mapped and aligned to show the presence/absence of chimeric YAC clones and provide detailed restriction knowledge for a large genomic region to help facilitate the positional cloning of genes.