Using Deficiency Mapping to Locate the Mutagen-sensitivity Gene mus108 in the Drosophila melanogaster Genome

DNA damage occurs regularly due to a variety of endogenous and exogenous sources. DNA repair corrects this damage, to ensure that DNA is passed faithfully to offspring and reduce an individual’s chance of developing cancer. The purpose of this research project was to map mus108, a DNA repair gene in Drosophila melanogaster. To locate this gene on the X chromosome, we conducted a deletion-mapping experiment by crossing mus108 mutant flies with flies carrying deletions on the X chromosome. To assess the mus phenotype in the deletion-mapping experiment, we used a mutagen sensitivity assay. In this assay, one brood of offspring was treated with water and the second brood was treated with methyl methanesulfonate (MMS), a DNA damaging agent. These crosses were repeated twice for two rounds of data, amounting to 5,439 flies scored. From this data, percent relative survival was calculated for each deletion. We have tentatively narrowed the genomic location of mus108 to one of these deletions. However, these results should be repeated before additional conclusions are drawn