Stem Cells in Primate Evolution

The human face is the product of developmental processes operating across diverse and overlapping spatiotemporal scales. To better understand how craniofacial variation is generated, in this chapter, we describe complementary theoretical frameworks for disentangling these interactions, alternative approaches to model phenotypic outcomes, and future challenges and opportunities. In the process, we discuss normal facial development in humans and comparative and experimental approaches utilizing a variety of model and non-model systems. We demonstrate how the integration of imaging, morphometrics, and developmental biology is helping to build a coherent picture of the developmental basis for craniofacial variation. Ultimately, we argue that a broader understanding of the interplay between development and evolution is relevant not only for how we interpret the range of normal and abnormal craniofacial variation found within humans but also the generation of phenotypes relevant to a range of evolutionary questions.