Homeotic (Hox) genes are transcription factors that dictate the development and compartmentalization (regionalization) of body parts in animals along the anterior-posterior (head to tail) axis. Using various insects and crustaceans, Dr. Nipam Patel studies how alterations in the expression of Hox genes could explain the evolution of specialized body parts in arthropods. Patel describes the spatially restricted patterns of Hox gene expression, explains the effects of Hox gene deletions, and how these phenotypes help us understand the manner in which Hox genes act to control the insect body plan. Taking a closer look at the pattern of the Hox gene Ultrabithorax (Ubx) in different insects, Patel summarizes the discovery that what drives changes in the number of wings during insect evolution is the not changes in the expression pattern of Ubx, but the regulation of its downstream gene targets.