The effect of caffeine on repair systems in oocytes of Drosophila melanogaster. I

Young Drosophila females were treated with caffeine, then mated for 24 h to males that had been irradiated with 2000 R X-irradiation, so that only mature spermatozoa were sampled. The radiation-induced frequency of dominant lethals and sex chromosome loss in the paternal genome was determined. The results show that treatment of females with caffeine leads to an increase in the frequencies of radiation-induced dominant lethals and to sex-chromosome loss.When young virgin females of the radioresistant stock RöI₂ were treated with caffeine and then irradiated with 3000 R X-irradiation, a striking increasein dominant lethals (in the maternal genome) was observed; caffeine treatment increased the X-ray response of the radioresistant stock to the level of the normal (+60) stock. It is suggested that caffeine reduces the efficiency of a system in Drosophila oocytes that repairs X-ray-produced chromosome breaks in both the paternal and maternal genomes.