The roundworm Caenorhabditis elegans (C. elegans) is a useful model organism to study the mechanism of sickness induced sleep (SIS). In this project, I use VC40258, a C. elegans strain from the million-mutation project (MMP) that has been identified to have a defect in SIS, to locate the gene responsible for the sleep defect. Specifically, I use linkage analysis to identify that the gene is located on either chromosome I or III. I then use MMP sequence variants on these chromosomes to formulate the hypothesis that the relevant variant is in the gene ceh-17, which has been previously shown to be responsible for SIS defective phenotypes in the strain IB16. Using a complementation test, I prove that the SIS-defective phenotypes in both VC40258 and IB16 are caused by mutations in the same gene. By identifying genes required for SIS, we can develop a better understanding of its mechanism, which is useful in the medical field for creating drug targets to modulate SIS in humans. Toward this translational goal, I am generating a database of worm sleep genes and their human orthologs.