Fig. 10. Molecular identification of VARICOSE. (A) Mapping strategy within a 1.6 MB region of chromosome 3. The approximate positions of the polymorphisms used in this study for high resolution mapping of recombination breakpoints are indicated at the top. Using 750 vcs F2 mapping cross plants, we identified six recombinants at the polymorphism indicated as VCSA, and 48 at the VCSI polymorphism. The DNA from the plants containing recombinant chromosomes were further analyzed at polymorphisms VCSB, MDC11, MRP15, and MAG2. The number of chromosomes that were still heterozygous at each position is indicated. (B) Depiction of the VCS gene; black boxes represent exons, the arrow on the bar indicates transcription direction for orientation of the 5' end of this gene. The position and nature of mutations in each vcs allele is indicated.