DESCRIPTION OF 31 YAC CONTIGS SPANNING THE MAJORITY OF ARABIDOPSIS-THALIANA CHROMOSOME-5

In order to generate a physical map of Arabidopsis thaliana chromosome 5, 142 molecular markers mapping to chromosome 5 have been used in co lony hybridization experiments with four Arabidopsis, ecotype Columbia , yeast artificial chromosome (YAC) libraries. This resulted in 634 YA C clones being anchored on chromosome 5. Southern blot analysis confir med their positioning and provided data, which along with knowledge of the sizes of all the YAC clones, enabled the clones to be arranged in to 31 contigs. Genetic mapping of markers located within 29 of these c ontigs on the Landsberg erecta/Columbia recombinant inbred lines allow ed positioning of the contigs along the chromosome. A high proportion of the YAC clones were found to contain chimaeric inserts. The availab ility of this YAC contig map will accelerate chromosome walking experi ments, provide substrates for large-scale genomic sequencing projects and facilitate the mapping of new probes to this chromosome.