MOLECULAR CHARACTERIZATION OF 4 SHRUNKEN MUTATIONS INDUCED IN MUTATOR LINES IN ZEA-MAYS L

Four shrunken (sh) mutants were independently isolated from Robertson's Mutator lines. A molecular analysis of each mutant determined that the lesions responsible for these mutations were due to DNA insertions located within the 5' untranslated region of the sh gene. Two of the insertions were similar in size to Mu1, the predominant transposable element found in all Mutator lines. However, one insertion was 5.5 kb, which, thus far, is the largest insertion observed in a mutant allele isolated from an active Mutator line. These results imply that DNA insertions other than Mu1 and Mu1.7 elements may be involved in. or activated by, Mutator.