PAG-I Plant Genome I Conference

Town & Country Conference Center, San Diego, CA, November, 1992.


PG-I: 5pg1

SATURATING THE LINKAGE MAP OF ARABIDOPSIS THALIANA WITH EMBRYONIC MUTATIONS.

Linda Franzmann, Elizabeth Yoon, and David Meinke, Department of Botany,Oklahoma State University, Stillwater,OK 74078.


The value of saturating genetic maps with visible markers has been demonstrated in a variety of experimental organisms. The mapping project outlined in this poster was designed to enhance the linkage map of Arabidopsis, complement the large multinational effort to characterize the Arabidopsis genome, and establish a valuable resource of recessive embryonic mutants defective in genes with known chromosomal locations. Our approach has been to determine recombination frequencies between embryonic mutations and visible markers [D.A. Patton, L.H. Franzmann, and D.W. Meinke, Mol. Gen. Genet. 227, 337-347 (1991)]. We have isolated and characterized 250 emb mutants of Arabidopsis defective in embryo development. This collection includes 178 mutants generated by Ken Feldmann following seed transformation. Forty three of these mutants appear to be tagged with T-DNA. We have now assigned 85 emb mutants to linkage groups and placed 40% of these mutants on the linkage map. Embryo-defective mutants are therefore without question the most common class of morphological marker on the linkage map of Arabidopsis. We hope to map the chromosomal locations of 100 total genes. Insertional mutants will be particularly useful for integrating the classical and molecular maps. Six tagged mutants unexpectedly exhibited linkage to visible markers on more than one chromosome. These mutants appear to contain chromosomal translocations associated with the site of T-DNA insertion. A significant percentage of mutants obtained from Ken Feldmann's lines may therefore contain plant chromosomal rearrangements. These translocations will be particularly valuable if the break point is associated with both a mutant phenotype (embryonic defect) and a molecular (T-DNA)marker. This research has been supported by NSF grant # DIR-9104215.


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