Results of the molecular (PCR) analysis of γ- and neutron-induced mutations of the white (w) gene localized in the Хchromosome of Drosophila melanogaster are reported (authors: E.V. Kravchenko, A.N. Russakovich, F. Elnoamani, S.V. Dubovik, S.E. Hassab-El-Nabi,, M.V. Aleksandrova, and I.D. Aleksandrov). Dose dependences of gene mutations induces by γrays and neutrons were preliminarily studied and found to be linear.

At the same time, on the basis of the genetic and cytological analysis, gene mutations not associated with chromosome aberrations were revealed. The PCR analysis of a considerable sample comprising seven spontaneous, 39 γ-induced, and 15 neutron-induced w mutations performed over the entire structural and functional gene map (5868 np) made it possible to establish four main categories of mutations with different characters of gene DNA changes, the relative frequency of which will be given. For a number of white mutations cytologically associated with inversions, it is found that the lesion point is localized outside rather than inside the gene, while the gene itself might have DNA microchanges not revealed by the PCR or small gene DNA losses. A comparative analysis of the relative frequencies of four mutation categories revealed by the PCR for y and w genes and autosomal b, cn, and vg genes allowed establishing both mechanisms for occurrence of radiation-induced DNA changes common for the above genes and gene-specific features in the pattern of their molecular mutagenesis, the nature of which is under discussion.