TY - JOUR
T1 - It takes two
T2 - Building the vertebrate skull from chondrocranium and dermatocranium
AU - Kathleen Pitirri, M.
AU - Kawasaki, Kazuhiko
AU - Richtsmeier, Joan T.
N1 - Publisher Copyright:
© 2020 Senckenberg Gesellschaft für Naturforschung.
PY - 2020
Y1 - 2020
N2 - In most modern bony vertebrates, a considerable portion of the chondrocranium remains cartilaginous only during a relatively small window of embryonic development, making it difficult to study this complex structure. Yet, the transient nature of some chondrocranial elements is precisely why it is so intriguing. Since the chondrocranium has never been lost in any vertebrate, its function is critical to craniofacial development, disease, and evolution. Experimental evidence for the various roles of the chondrocranium is limited, and though snapshots of chondrocranial development in various species at isolated time points are valuable and informative, these cannot provide the data needed to determine the functions of the chondrocranium, or its relationship to the dermatocranium in evolution, in development, or in disease. Observations of the spatiotemporal associations of chondrocranial cartilage, cartilage bone, and dermal bone over early developmental time are available for many vertebrate species and these observations represent the data from which we can build hypotheses. The testing of those hypotheses requires precise control of specific variables like developmental time and molecular signaling that can only be accomplished in a laboratory setting. Here, we employ recent advances in contrast-enhanced micro computed tomography to provide novel 3D reconstructions of the embryonic chondrocranium in relation to forming dermal and cartilage bones in laboratory mice across three embryonic days (E13.5, E14.5, and E15.5). Our observations provide support for the established hypothesis that the vertebrate dermal (exo-) skeleton and endoskeleton evolved as distinct structures and remain distinct. Additionally, we identify spatiotemporal patterning in the development of the lateral wall, roof, and braincase floor of the chondrocranium and the initial mineralization and growth of the bones associated with these cartilages that provides support for the hypothesis that the chondrocranium serves as a scaffold for developing dermatocranial bones. The experimental protocols described and data presented provide tools for further experimental work on chondrocranial development.
AB - In most modern bony vertebrates, a considerable portion of the chondrocranium remains cartilaginous only during a relatively small window of embryonic development, making it difficult to study this complex structure. Yet, the transient nature of some chondrocranial elements is precisely why it is so intriguing. Since the chondrocranium has never been lost in any vertebrate, its function is critical to craniofacial development, disease, and evolution. Experimental evidence for the various roles of the chondrocranium is limited, and though snapshots of chondrocranial development in various species at isolated time points are valuable and informative, these cannot provide the data needed to determine the functions of the chondrocranium, or its relationship to the dermatocranium in evolution, in development, or in disease. Observations of the spatiotemporal associations of chondrocranial cartilage, cartilage bone, and dermal bone over early developmental time are available for many vertebrate species and these observations represent the data from which we can build hypotheses. The testing of those hypotheses requires precise control of specific variables like developmental time and molecular signaling that can only be accomplished in a laboratory setting. Here, we employ recent advances in contrast-enhanced micro computed tomography to provide novel 3D reconstructions of the embryonic chondrocranium in relation to forming dermal and cartilage bones in laboratory mice across three embryonic days (E13.5, E14.5, and E15.5). Our observations provide support for the established hypothesis that the vertebrate dermal (exo-) skeleton and endoskeleton evolved as distinct structures and remain distinct. Additionally, we identify spatiotemporal patterning in the development of the lateral wall, roof, and braincase floor of the chondrocranium and the initial mineralization and growth of the bones associated with these cartilages that provides support for the hypothesis that the chondrocranium serves as a scaffold for developing dermatocranial bones. The experimental protocols described and data presented provide tools for further experimental work on chondrocranial development.
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U2 - 10.26049/VZ70-4-2020-04
DO - 10.26049/VZ70-4-2020-04
M3 - Article
AN - SCOPUS:85095614314
SN - 1864-5755
VL - 70
SP - 587
EP - 600
JO - Vertebrate Zoology
JF - Vertebrate Zoology
IS - 4
ER -