Low-activity allele of copper-zinc superoxide dismutase (CuZnSOD) in Drosophila increases paraquat genotoxicity but does not affect near UV radiationdamage

Different types of mutations and DNA-damage profiles induced by near-UV rad iation and the superoxide anion (O-2) indicate separate lesions and (or) me chanisms of mutagenesis. Despite a wealth of data, it is still unclear whet her variations in the activity levels of antioxidant enzymes naturally pres ent in suboptimal concentrations are among the underlying causes of the inc rease of near UV radiation genotoxicity. We incorporated a low-activity all ele of copper-zinc superoxide dismutase (CuZnSOD), recovered from natural p opulations of Drosophila melanogaster, into standard marked strains and emp loyed a somatic mutation and recombination test (SMART) to compare paraquat and near UV radiation genotoxicity in these strains. Our results show that , although the low-activity CuZnSOD allele of D. melanogaster confers hyper sensitivity to paraquat, the near UV radiation damage was not affected.