The exposure of living cells to ionizing radiation can induce several types of mutations, which can influence the growth of the mutant colonies and subclones. The effects of the accelerated Ne-20 ions on the Chinese hamster cells (line V-79) are studied. The irradiation with Ne-20 ions (Ea = 53 meV/nucleon, LET ~ 138 keV/um) was conducted on the "Genom" setup of the FLNR accelerator U-400M; the cells were exposed to doses 0.5, 1 and 2 Gy. The mutations were studied in the HPRT gene which is responsible for the synthesis of purines through the “salvage pathway”. This work is focusing particularly on the changes in the rate of mutagenesis with increasing expression time (time for the expression of mutations) and the differences in the time of growth of isolated mutants. It is shown that the mutant frequency of radiation induced mutants is growing with the expression time, reaching maximum around 15-­18 days (30­-40 generations) after exposure, and decreasing back to the levels of spontaneous mutants. The effects of neon ions are compared to older results – mainly to the irradiation with 18O (36 MeV/nucleon; LET ~ 116 keV/µm).
Unusual morphological signs of the mutant subclones are discussed.