Distal-less (Dll) is a master regulator gene responsible for proximal-distal axis formation as well as distal appendage identity. Previous research showed that the expression of Dll is maintained through a feedback loop with Disco, a C2H2 zinc finger transcription factor. In this project I investigate recent suggestions that disco may play additional roles as a cofactor or downstream target of Dll during appendage development. I confirm previous research that the presence of Dll is sufficient to turn on disco. I found that the presence of ectopic Dll in the wing discs activates Dll subordinate genes in cells where they are not normally expressed. I again performed experiments confirming previous reports that ectopic expression of Dll in the wing tissue is sufficient to cause the appearance of ectopic legs. I then showed that when Dll is expressed ectopically in the absence of disco, there ectopic appendages similar to those formed in the presence of disco. Put together, my results suggest that disco is does not function as a cofactor or downstream target required for the development and differentiation of Drosophila ventral appendages. / Thesis / Master of Science (MSc)