Morphogenesis of the zebrafish jaw: development beyond the embryo.

The zebrafish has emerged as an important model for vertebrate development as it relates to human health and disease. Work in this system has provided significant insights into the variety of genetic signals that direct the cellular activities and tissue interactions necessary for proper assembly of the pharyngeal skeleton. Unfortunately our understanding of craniofacial development beyond embryonic stages is far less complete. Stated another way, we know a great deal about the early patterning of the skull, but we know comparatively little about how mature craniofacial shape is determined and maintained over time. Here we propose ways to expand the current molecular genetic paradigm beyond the embryo to gain an understanding of the processes and mechanisms that guide growth and remodeling of mineralized craniofacial, skeletal, and dental tissues. First, we discuss sources of adult mutant phenotypes that can be used to study of postembryonic development. Next, we review salient quantitative methods that are necessary to define complex adult phenotypes. We also discuss how other organismal systems can be used to inform and complement studies in zebrafish. We conclude by discussing the implications for such studies within the context of furthering an understanding of the etiology and pathophysiology of human craniofacial malformations, as well as informing an understanding of adaptive craniofacial variation among natural populations.