Summary
o2-m(r) is an unstable allele of the O2 locus responding to the regulatory element Bg by somatic reversion. The spontaneous occurrence and the properties of the components of this system of controlling elements have been investigated. The system appears to have some degree of specificity for the O2 locus, because the majority of spontaneous O2 mutations are responsive to Bg. The component at the controlled locus undergoes frequent changes in state, while the Bg element appears more stable. Bg activity was revealed in 11 out of 108 open-pollinated varieties of maize. Most of the newly isolated Bg elements are linked with the O2 locus. The timing of induction of reversion events (which are restricted to mitotic division leading to egg or pollen maturation and to the developing endosperm) appears to correlate with the degree of linkage between Bg and the O2 locus. Germinal reversions of o2-m(r) to wild type give rise with a frequency around 5×10-4 to unstable phenotypes. Some peculiar features of the o2-m(r)-Bg system of controlling elements are discussed.
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Montanelli, C., Di Fonzo, N., Marotta, R. et al. Occurrence and behavior of the components of the 02-m(r)-Bg system of maize controlling elements. Mol Gen Genet 197, 209–218 (1984). https://doi.org/10.1007/BF00330965
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DOI: https://doi.org/10.1007/BF00330965