 The Bicoid, Hunchback and Caudal proteins in turn regulate the transcription of gap genes such as "giant", "knirps", "Krüppel", and "tailless" in a striped pattern, creating the first level of structures that will become segments.The proteins from these in turn control the pair-rule genes, which in the next stage set up 7 bands across the embryo's long axis.Finally, the segment polarity genes such as "engrailed" split each of the 7 bands into two, creating 14 future segments.