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Abstract
The purpose of this research was to characterize mutations induced by the Ac2 elements. The Ac2 element was identified by its ability to mobilize the Ds2 element present at the bz2 locus. Ac2 causes late transposition and with increased copy number increases the frequency of transposition. By screening for Ac2 induced mutations, a1, bz1, and c1 mutants have been isolated. A 700 bp insertion at the a1-m3302 mutant has been cloned and sequenced. The sequence data showed the insertional element at the a1-m 3302 is a rDt element. In the presence of Dt, it is a stable a1 mutant. In the presence of Dt, it shows an unstable phenotype with somatic and germinal revertants. The bz1-m 3310 mutant is an autonomous mutation. The mutable phenotype is composed of small sectors with an occasional kernel having a larger sector. The bz1-m 3310 exhibits a direct dosage effect such that frequency of transposition increases as the number of mutable alleles increase. The insertion at the bz1-m 3310 is 4.5 kb and located at the first exon of bz1 gene. Sequence analysis of the clones from the element have a high degree of identity with the Ac element. The c1-m 3189 mutant is a nonautonomous mutation. This allele responds to the presence of Ac2 in a single copy by making small sectors of colored aleurone. Germinal revertants have been obtained in response to Ac2.
