Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw

Abstract

The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition.

Making and shaping endochondral and intramembranous bones

“…6D). Humans and rats, but not mice, opposums and guinea pigs, develop a coronoid secondary cartilage 312 . Despite the lack of a coronoid cartilage in mice (Fig.…”

Species-specific sensitivity to TGFβ signaling and changes to the Mmp13 promoter underlie avian jaw development and evolution

“…While our results indicate that promoter evolution may play an important role in the species-specific expression of Mmp13 and in this way could influence the establishment of jaw length in quail versus duck via bone resorption, the potential contributions from additional levels of Mmp13 regulation, multiple Mmps, as well as different members and targets of TGFβ and other signaling pathways remain vast (Mina, 2001b;Mina, 2001a;Depew et al, 2002;Mina et al, 2002;Chakraborti et al, 2003;Oka et al, 2007;Havens et al, 2008;Balic et al, 2009;Fanjul-Fernandez et al, 2010;Fish et al, 2011;Young et al, 2019). In prior studies we have found that NCM-mediated programs underlying jaw development in quail and duck also vary due to species-specific differences in the cell biological properties of NCM and in the physical and signaling interactions between NCM and adjacent tissues (Schneider and Helms, 2003;Schneider, 2007;Eames and Schneider, 2008;Merrill et al, 2008;Tokita and Schneider, 2009;Solem et al, 2011;Fish and Schneider, 2014b;Fish et al, 2014;Hall et al, 2014;Ealba et al, 2015;Schneider, 2015;Woronowicz et al, 2018;Woronowicz and Schneider, 2019).…”

Foxg1Organizes Cephalic Ectoderm to Repress Mandibular Fate, Regulate Apoptosis, Generate Choanae, Elaborate the Auxiliary Eye and Pattern the Upper Jaw

“…Therefore, as an initial read-out of the patterning road-map of the cephalic ectoderm and the λ-junction we examined the expression patterns of Bmp4 at E10. 25 and Fgf8 at E10.75 ( Figure 10). While we found, as expected, that normal distal mdBA1 Bmp4 expression was robust in double mutant embryos, we also unexpectedly found a near complete loss of junctional Bmp4 expression.…”

“…As the vast majority of vertebrates are gnathostomes, and thus possess jaws, the true enormity of the observed radiation and diversification of vertebrates must be regarded in the particular light of the acquisition and modification of jaws . Jaws are prehensile oral apparatuses that can be further defined by their possession of two appositional units -the upper and lower arcades -that are articulated (hinged) and which largely arise during development from the first branchial arch (BA1) (5)(6)(7)(8)(9)(10)(11)(12)(23)(24)(25)(26)(27)(28)(29)(30)(31).…”