A STUDY OF rDNA MAGNIFICATION PHENOMENON IN A REPAIR-RECOMBINATION DEFICIENT MUTANT OF DROSOPHILA MELANOGASTER

Lino C. Polito ¹, Daniela Cavaliere ¹, Anna Zazo ¹, and Maria Furia ²

¹ International Institute of Genetics and Biophysics, CNR, Naples
² Institute of General Biology and Genetics, Faculty of Sciences, University of Naples

The rDNA magnification process consists of a rapid and inheritable rDNA increase occurring in bobbed males: in a few generations the bb loci acquire the wild-type rDNA value and reach a bb⁺ phenotype.—We have analyzed the rDNA magnification process in the repair-recombination-deficient mutant mei9^a, both at the phenotypical and rDNA content levels. In mei9^a bb double mutants the recovery of bb⁺ phenotype is strongly disturbed and the rDNA redundancy value fails to reach the wild-type level. The strong effect of this meiotic mutation on rDNA magnification suggests a close relationship between this phenomenon and the repair-recombination processes.