title: Regulation of Jaw Length During Development, Disease, and Evolution.
abstract: Molecular and cellular mechanisms that control jaw length are becoming better understood. This is significant since the jaws are not only critical for species-specific adaptation and survival, but they are often affected by a variety of size-related anomalies including mandibular hypoplasia, retrognathia, asymmetry, and clefting. This chapter overviews how jaw length is established during the allocation, proliferation, differentiation, and growth of jaw precursor cells, which originate from neural crest mesenchyme (NCM). The focus is mainly on results from experiments transplanting NCM between quail and duck embryos. Quail have short jaws whereas those of duck are relatively long. Quail-duck chimeras reveal that the determinants of jaw length are NCM mediated throughout development and include species-specific differences in jaw progenitor number, differential regulation of various signaling pathways, and the autonomous activation of programs for skeletal matrix deposition and resorption. Such insights help make the goal of devising new therapies for birth defects, diseases, and injuries to the jaw skeleton seem ever more likely.
authors.affiliation: Department of Orthopaedic Surgery, University of California at San Francisco, San Francisco, California, USA. Electronic address: rich.schneider@ucsf.edu.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Schneider
mesh_terms: D000818:Animals; D019521:Body Patterning; D004372:Ducks; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D007568:Jaw / Q000033:anatomy & histology / Q000196:embryology* / Q000378:metabolism; D007571:Jaw Diseases / Q000196:embryology / Q000235:genetics; D008648:Mesoderm / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D009432:Neural Crest / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D011784:Quail; D013045:Species Specificity
keywords: Bone resorption; Cartilage and bone deposition; Cranial neural crest; Craniofacial defects; Evolutionary developmental biology; Jaw length; Quail–duck chimeras; Skeletal progenitor cells