Plant & Animal Genome VI Conference

W76

PHYSICAL MAPPING OF THE ARABIDOPSIS THALIANA (Arabidopsis thaliana) GENOME USING BACTERIAL ARTIFICIAL CHROMOSOMES (BACs)

Max-Planck-Institut fuer molekulare Pflanzenphysiologie, Karl-Liebknecht-Str.25, Haus 20, 14476 Golm, Germany

An Arabidopsis thaliana bacterial artificial chromosome (BAC) library has been established through partial EcoRI digestion of HMW-DNA of the Col-0 ecotype of Arabidopsis thaliana and insertion into a modified pBeloBAC-vector (pBeloBAC-Kan, Km^r). This library consits of 10,752 clones that exhibit a mean insert size of about 100 kb (in the range of 80kb to 120 kb for 85% of the clones). Hybridizations with nuclear repetitive elements revealed 11%, 1.5%, and 3% of the clones carrying 18-25S rDNA, 5S rDNA, and the 180 bp and 160 bp centromeric repeats, respectively. Less than 0.1% of the clones contain plastid DNA (K. Dewar, unpublished results). A "sampling without replacement" approach for mapping is currently being performed through hybridization of a high number of BAC endprobes to the library spotted on high density filters. This approach is complemented by an international collaborative effort to anchor contigs by hybridization of mapped markers, BACs, and YACs which involved a major contribution by K. Dewar and J. Ecker, Philadelphia, USA (chromosome 1 specific markers and BACs). Hithertoo, 2362 probes (mapped markers, BAC ends, and total BACs) identified a total of 6699 clones representing 2/3 of the total library. These clones fall into 474 contigs among which further 157 potential connections exist. The results of this mapping project are displayed at the Arabidopsis BAC data www site (http://www.mpimp-golm.mpg.de/private_workgroups/pg_101/bac.html).