Abstract
Transposon mutagenesis has been used to isolate mutable alleles at the Opaque-2 (O2) locus of maize. Plants with the Activator-Dissociation (Ac-Ds) system of transposable elements and O2 were crossed as males to a stable o2 tester line. Among a population of 200,000 kernels, 198 exceptional kernels with somatic instability were recovered. In four cases, designated O2-m1, o2-m2, O2-m3 and O2-m4, variegated phenotypes appeared in F2 and subsequent generations. Genetic analyses indicated that the presence of Ds near or within the O2 gene was responsible for the observed somatic instability at the O2 locus. The phenotypes of the newly induced alleles were of two types. Alleles O2-m1, O2-m3 and O2-m4, in the absence of Ac, were characterized by kernel phenotypes indistinguishable from the wild type; in the presence of Ac they generated kernels with opaque sectors interspersed within a vitreous background. In contrast, the mutable allele o2-m2, in the absence of Ac, was characterized by kernels with a recessive phenotype similar to o2 recessive mutants. In the presence of Ac, it reverted somatically to wild-type-producing kernels with vitreous spots in an o2 background. The association of the Ds element with the O2 locus may prove a valuable tool directed to the isolation of DNA fragments bearing the O2 gene.
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Selected References
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- McCLINTOCK B. Chromosome organization and genic expression. Cold Spring Harb Symp Quant Biol. 1951;16:13–47. doi: 10.1101/sqb.1951.016.01.004. [DOI] [PubMed] [Google Scholar]
- McClintock B. Induction of Instability at Selected Loci in Maize. Genetics. 1953 Nov;38(6):579–599. doi: 10.1093/genetics/38.6.579. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nevers P., Saedler H. Transposable genetic elements as agents of gene instability and chromosomal rearrangements. Nature. 1977 Jul 14;268(5616):109–115. doi: 10.1038/268109a0. [DOI] [PubMed] [Google Scholar]
- O'Reilly C., Shepherd N. S., Pereira A., Schwarz-Sommer Z., Bertram I., Robertson D. S., Peterson P. A., Saedler H. Molecular cloning of the a1 locus of Zea mays using the transposable elements En and Mu1. EMBO J. 1985 Apr;4(4):877–882. doi: 10.1002/j.1460-2075.1985.tb03713.x. [DOI] [PMC free article] [PubMed] [Google Scholar]