The Effect of Spermidine on the Rate of Sex-Linked Recessive Lethals Caused by X-Ray in Drosophila Melanogaster
The problem. Spermidine is a polyamine naturally occurring in many organisms including "Drosophila melanogaster". It has been shown to decrease the heat denaturation of DNA by binding to the DNA double helix. The agent has also decreased the development of resistance of bacteria to a particular antibiotic. The major objective of this study was to determine if treatment to "Drosophila" with a given concentration of spermidine prior to X-ray exposure would change the expected number of sex-linked recessive lethal mutations. Procedure. Adult male wild-type "Drosophila" were treated in four ways. The four treatments, administered via feeding in a medium with dimethyl sulfoxide, were Control, X-ray, spermidine, or spermidine and X-ray. Treated adult males were mated in groups of twenty with twenty virgin "Basc" females. The "Basc" technique for detection of X-Linked recessive lethal mutations was followed. Mutation frequencies were calculated and data was submitted to the Kastenbaum-Boman test. Findings. The control group exhibited a mutation frequency of 0.68% which showed no significant difference compared with the 0.59% mutation frequency with spermidine. The mutation frequency for the X-ray only treatment was 2.62% and the mutation frequency for the spermidine and X-ray treatment was 2.86%. Conclusions. The data obtained from this study showed that pretreatment with spermidine had no significant effect on decreasing the expected number of sex-linked recessive lethal mutations caused by X-irradiation exposure. Spermidine alone was shown to have no mutagenic effect, but in combination with irradiation a slight, statistically insignificant, increase was found.
31 leaves. Advisor: Michael E. Myszewski