ASX (Additional sex combs)

ASX, or Additional sex combs, is a gene in fruit flies (Drosophila melanogaster) that plays a crucial role in development, particularly in determining the identity of certain body segments. It is part of the homeotic gene complex, which regulates the formation of structures like antennae and legs. When ASX functions normally, it helps ensure proper development by controlling gene expression during early stages. Mutations can lead to abnormal structures or segment transformations. Overall, ASX is essential for proper segment differentiation, contributing to the correct formation of body parts in the developing fly.