AN ARABIDOPSIS-THALIANA RFLP MAPPING SET TO LOCALIZE MUTATIONS TO CHROMOSOMAL REGIONS

Mapping of newly identified Arabidopsis thaliana mutants is an important step towards their molecular characterization and the attempt to saturate the genome by known mutations. The classical genetic analysis using phenotypic tester lines is well-established, but laborious, time-consuming and potentially ambiguous. An alternative molecular strategy was developed that is based on RFLPs. Subcloned DNA markers that detect only segregating RFLP bands distinguishing A. thaliana ecotype Landsberg from Columbia or Enkheim after EcoRI restriction digestion compose an Arabidopsis RFLP mapping set (ARMS). Up to 13 markers uniformly cover the five A. thaliana chromosomes and can be scored in only two successive Southern experiments on a single blot without mutual interference of the signals. Thus, this system allows a simple, reliable, rapid and especially inexpensive mapping of any monogenic mutant locus to the A. thaliana chromosomes. Several loci can be analysed in one experiment if the respective blots are hybridized together. This paper demonstrates the mapping of two recessive mutants affecting the development of A. thaliana leaves which had been generated in the Columbia and Enkheim ecotype by analysing less than 20 F2 individuals. Further markers to refine or verify the result on the same blot can be chosen out of 14 additional probes detecting single segregating EcoRI polymorphic bands as well.