Abstract
Morphological integration and modularity are concepts widely used to understand human and non-human primate skull evolution. However, most studies focus on patterns of covariation and correlation rather than the processes that generate those patterns. The discovery that many key signaling pathways are conserved across a wide variety of animal phylogenies has allowed the use of animal models to identify processes that influence patterns and magnitudes of variation in skeletal structures. This chapter presents a study on the differential effects of upregulation of Sonic Hedgehog (SHH) signaling on the murine skull. SHH is an evolutionarily conserved gene critical for patterning of the mammalian facial skeleton. The results presented here provide insight into potential genetic processes that structure modularity in the primate, and mammalian, skull.