1
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Razmadze D, Salomies L, Di-Poï N. Squamates as a model to understand key dental features of vertebrates. Dev Biol 2024; 516:1-19. [PMID: 39069116 DOI: 10.1016/j.ydbio.2024.07.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 06/11/2024] [Accepted: 07/23/2024] [Indexed: 07/30/2024]
Abstract
Thanks to their exceptional diversity, teeth are among the most distinctive features of vertebrates. Parameters such as tooth size, shape, number, identity, and implantation can have substantial implications for the ecology and certain social behaviors of toothed species. Despite decades of research primarily focused on mammalian dentition, particularly using the laboratory mouse model, squamate reptiles ("lizards" and snakes) offer a wide array of tooth types and dentition variations. This diversity, which includes differences in size, shape, function, and replacement capacity, provides invaluable opportunities for investigating these fundamental properties. The central bearded dragon (Pogona vitticeps), a popular pet species with well-established husbandry practices, is of particular interest. It features a broad spectrum of morphs and spontaneous mutants and exhibits a wide range of heterodont phenotypes, including variation in the size, shape, number, implantation, and renewal of teeth at both posterior and anterior positions. These characteristics position the species as a crucial model organism for developmental studies in tooth research and for gaining deeper insights into evolutionary patterns of vertebrate dentitions. In this article, we provide an overview of the current understanding of squamate dentition, its diversity, development, and replacement. Furthermore, we discuss the significant advantages offered by squamate species as model organisms for investigating the evolutionary and developmental aspects of vertebrate dentition.
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Affiliation(s)
- Daria Razmadze
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00014, Helsinki, Finland
| | - Lotta Salomies
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00014, Helsinki, Finland
| | - Nicolas Di-Poï
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, 00014, Helsinki, Finland.
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2
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Fang Z, Atukorallaya D. Count Me in, Count Me out: Regulation of the Tooth Number via Three Directional Developmental Patterns. Int J Mol Sci 2023; 24:15061. [PMID: 37894742 PMCID: PMC10606784 DOI: 10.3390/ijms242015061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/05/2023] [Accepted: 10/08/2023] [Indexed: 10/29/2023] Open
Abstract
Tooth number anomalies, including hyperdontia and hypodontia, are common congenital dental problems in the dental clinic. The precise number of teeth in a dentition is essential for proper speech, mastication, and aesthetics. Teeth are ectodermal organs that develop from the interaction of a thickened epithelium (dental placode) with the neural-crest-derived ectomesenchyme. There is extensive histological, molecular, and genetic evidence regarding how the tooth number is regulated in this serial process, but there is currently no universal classification for tooth number abnormalities. In this review, we propose a novel regulatory network for the tooth number based on the inherent dentition formation process. This network includes three intuitive directions: the development of a single tooth, the formation of a single dentition with elongation of the continual lamina, and tooth replacement with the development of the successional lamina. This article summarizes recent reports on early tooth development and provides an analytical framework to classify future relevant experiments.
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Affiliation(s)
| | - Devi Atukorallaya
- Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2, Canada;
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3
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Dumont M, Milgram J, Herrel A, Shahar R, Shacham B, Houssin C, Delapré A, Cornette R, Segall M. Show Me Your Teeth And I Will Tell You What You Eat: Differences in Tooth Enamel in Snakes with Different Diets. Integr Comp Biol 2023; 63:265-275. [PMID: 37156518 DOI: 10.1093/icb/icad028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/02/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023] Open
Abstract
Teeth are composed of the hardest tissues in the vertebrate body and have been studied extensively to infer diet in vertebrates. The morphology and structure of enamel is thought to reflect feeding ecology. Snakes have a diversified diet, some species feed on armored lizards, others on soft invertebrates. Yet, little is known about how tooth enamel, and specifically its thickness, is impacted by diet. In this study, we first describe the different patterns of enamel distribution and thickness in snakes. Then, we investigate the link between prey hardness and enamel thickness and morphology by comparing the dentary teeth of 63 species of snakes. We observed that the enamel is deposited asymmetrically at the antero-labial side of the tooth. Both enamel coverage and thickness vary a lot in snakes, from species with thin enamel, only at the tip of the tooth to a full facet covered with enamel. There variations are related with prey hardness: snakes feeding on hard prey have a thicker enamel and a lager enamel coverage while species. Snakes feeding on softer prey have a thin enamel layer confined to the tip of the tooth.
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Affiliation(s)
- Maïtena Dumont
- Laboratory of Bone Biomechanics, Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, HUJI, Rehovot, Israel
| | - Joshua Milgram
- Laboratory of Bone Biomechanics, Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, HUJI, Rehovot, Israel
| | - Anthony Herrel
- Mécanismes Adaptatifs et Evolution, UMR 7179, Muséum National d'Histoire Naturelle CNRS, Paris, France
| | - Ron Shahar
- Laboratory of Bone Biomechanics, Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, HUJI, Rehovot, Israel
| | - Boaz Shacham
- National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Céline Houssin
- Institut de Systématique Evolution, Biodiversité (ISYEB), UMR 7205, Muséum National d'Histoire naturelle CNRS, SU, EPHE, UA, CP 50, Paris, France
| | - Arnaud Delapré
- Institut de Systématique Evolution, Biodiversité (ISYEB), UMR 7205, Muséum National d'Histoire naturelle CNRS, SU, EPHE, UA, CP 50, Paris, France
| | - Raphaël Cornette
- Institut de Systématique Evolution, Biodiversité (ISYEB), UMR 7205, Muséum National d'Histoire naturelle CNRS, SU, EPHE, UA, CP 50, Paris, France
| | - Marion Segall
- Institut de Systématique Evolution, Biodiversité (ISYEB), UMR 7205, Muséum National d'Histoire naturelle CNRS, SU, EPHE, UA, CP 50, Paris, France
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
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4
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Mitsiadis TA, Pagella P, Capellini TD, Smith MM. The Notch-mediated circuitry in the evolution and generation of new cell lineages: the tooth model. Cell Mol Life Sci 2023; 80:182. [PMID: 37330998 DOI: 10.1007/s00018-023-04831-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/19/2023] [Accepted: 06/09/2023] [Indexed: 06/20/2023]
Abstract
The Notch pathway is an ancient, evolutionary conserved intercellular signaling mechanism that is involved in cell fate specification and proper embryonic development. The Jagged2 gene, which encodes a ligand for the Notch family of receptors, is expressed from the earliest stages of odontogenesis in epithelial cells that will later generate the enamel-producing ameloblasts. Homozygous Jagged2 mutant mice exhibit abnormal tooth morphology and impaired enamel deposition. Enamel composition and structure in mammals are tightly linked to the enamel organ that represents an evolutionary unit formed by distinct dental epithelial cell types. The physical cooperativity between Notch ligands and receptors suggests that Jagged2 deletion could alter the expression profile of Notch receptors, thus modifying the whole Notch signaling cascade in cells within the enamel organ. Indeed, both Notch1 and Notch2 expression are severely disturbed in the enamel organ of Jagged2 mutant teeth. It appears that the deregulation of the Notch signaling cascade reverts the evolutionary path generating dental structures more reminiscent of the enameloid of fishes rather than of mammalian enamel. Loss of interactions between Notch and Jagged proteins may initiate the suppression of complementary dental epithelial cell fates acquired during evolution. We propose that the increased number of Notch homologues in metazoa enabled incipient sister cell types to form and maintain distinctive cell fates within organs and tissues along evolution.
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Affiliation(s)
- Thimios A Mitsiadis
- Institute of Oral Biology, Centre for Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland.
| | - Pierfrancesco Pagella
- Institute of Oral Biology, Centre for Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
- Wallenberg Center for Molecular Medicine (WCMM) and Department of Biomedical and Clinical Sciences, Linköpings Universitet, 581 85, Linköping, Sweden
| | - Terence D Capellini
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Moya Meredith Smith
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, King's College London, London, UK
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5
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Daza JD, Krakoski EC, Gamble T, Bauer AM. Hyperdontia in the Paraguayan Martha's marked gecko (Homonota marthae: Phyllodactylidae: Squamata). Anat Rec (Hoboken) 2023; 306:692-695. [PMID: 36102792 DOI: 10.1002/ar.25077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/23/2022] [Accepted: 08/26/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Juan D Daza
- Department of Biological Sciences, Sam Houston State University, Huntsville, Texas, USA
| | - Emma C Krakoski
- Department of Biological Sciences, Sam Houston State University, Huntsville, Texas, USA
| | - Tony Gamble
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, USA.,Milwaukee Public Museum, Milwaukee, Wisconsin, USA.,Bell Museum of Natural History, University of Minnesota, St Paul, Minnesota, USA
| | - Aaron M Bauer
- Department of Biology and Center for Biodiversity and Ecosystem Stewardship, Villanova University, Villanova, Pennsylvania, USA
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6
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Fenelon JC, Bennetts A, Anthwal N, Pyne M, Johnston SD, Evans AR, Tucker AS, Renfree MB. Getting out of a mammalian egg: the egg tooth and caruncle of the echidna. Dev Biol 2023; 495:8-18. [PMID: 36565838 DOI: 10.1016/j.ydbio.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/16/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
In the echidna, after development in utero, the egg is laid in the pouch and incubated for 10 days. During this time, the fetuses develop an egg tooth and caruncle to help them hatch. Using rare and unprecedented access to limited echidna pre- and post-hatching tissues, development of the egg tooth and caruncle were assessed by micro-CT, histology and immunofluorescence. Unlike therian tooth germs that develop by placode invagination, the echidna egg tooth developed by evagination, similar to the first teeth in some reptiles and fish. The egg tooth ankylosed to the premaxilla, rather than forming a tooth root with ligamentous attachment found in other mammals, with loss of the egg tooth associated with high levels of activity odontoclasts and apoptosis. The caruncle formed as a separate mineralisation from the adjacent nasal capsule, and as observed in birds and turtles, the nasal region epithelium on top of the nose expressed markers of cornification. Together, this highlights that the monotreme egg tooth shares many similarities with typical reptilian teeth, suggesting that this tooth has been conserved from a common ancestor of mammals and reptiles.
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Affiliation(s)
- Jane C Fenelon
- School of BioSciences, The University of Melbourne, Victoria, 3010, Australia.
| | - Abbie Bennetts
- School of BioSciences, The University of Melbourne, Victoria, 3010, Australia
| | - Neal Anthwal
- Centre for Craniofacial and Regenerative Biology, King's College London, London, SE1 9RT, UK
| | - Michael Pyne
- Currumbin Wildlife Sanctuary, Currumbin, Queensland, 4223, Australia
| | - Stephen D Johnston
- School of Agriculture and Food Sciences, The University of Queensland, Gatton, 4343, Australia
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia; Geosciences, Museums Victoria, Melbourne, Victoria, 3001, Australia
| | - Abigail S Tucker
- Centre for Craniofacial and Regenerative Biology, King's College London, London, SE1 9RT, UK
| | - Marilyn B Renfree
- School of BioSciences, The University of Melbourne, Victoria, 3010, Australia
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7
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Kavková M, Šulcová M, Zikmund T, Pyszko M, Kaiser J, Buchtová M. X-ray microtomography imaging of craniofacial hard tissues in selected reptile species with different types of dentition. Gigascience 2022; 11:6543636. [PMID: 35254425 PMCID: PMC8900495 DOI: 10.1093/gigascience/giac016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/19/2021] [Accepted: 01/28/2022] [Indexed: 12/23/2022] Open
Abstract
Background Reptiles exhibit a large heterogeneity in teeth morphology. The main variability comprises the different tooth shape, the type of tooth attachment to the underlying bone, or the ability to replace the teeth. Findings Here, we provide full datasets of microtomography scans and 3D models of reptilian dentitions and skulls. We selected representative species for each of 9 reptilian families on the basis of their characteristic dental features. Because there are ≥4 different types of tooth-bone attachments, ranging from the mammalian-like thecodont attachment found in crocodilians to the simple acrodont implantation observed in some lizards, we aimed to evaluate species with different types of tooth-bone attachments. Moreover, another interesting feature varying in reptilian species is the complexity of tooth shape or the number of tooth generations, which can be associated with the type of tooth attachment to the jawbone. Therefore, selected model species also include animals with distinct tooth morphology along the jaw or different number of tooth generations. The development of tooth attachment and relationship of the tooth to the jaw can be further analysed in detail on a large collection of pre-hatching stages of chameleon. Next, we introduce different possibilities for how these datasets can be further used to study tooth-bone relationships or tooth morphology in 3D space. Moreover, these datasets can be valuable for additional morphological and morphometric analyses of reptilian skulls or their individually segmented skeletal elements. Conclusions Our collection of microcomputed tomography scans can bring new insight into dental or skeletal research. The broad selection of reptilian species, together with their unique dental features and high quality of these scans including complete series of developmental stages of our model species and provide large opportunities for their reuse. Scans can be further used for virtual reality, 3D printing, or in education.
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Affiliation(s)
- Michaela Kavková
- Central European Institute of Technology, Brno University of Technology, 616 69 Brno, Czech Republic
| | - Marie Šulcová
- Department of Experimental Biology, Faculty of Science, Masaryk University, 612 42 Brno, Czech Republic.,Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and Genetics, v.v.i., Czech Academy of Sciences, 602 00 Brno, Czech Republic
| | - Tomáš Zikmund
- Central European Institute of Technology, Brno University of Technology, 616 69 Brno, Czech Republic
| | - Martin Pyszko
- Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, 625 00 Brno, Czech Republic
| | - Jozef Kaiser
- Central European Institute of Technology, Brno University of Technology, 616 69 Brno, Czech Republic
| | - Marcela Buchtová
- Department of Experimental Biology, Faculty of Science, Masaryk University, 612 42 Brno, Czech Republic.,Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and Genetics, v.v.i., Czech Academy of Sciences, 602 00 Brno, Czech Republic
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8
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Louryan S, Choa-Duterre M, Lejong M, Vanmuylder N. Evolution and development of parrot pseudoteeth. J Morphol 2021; 283:207-218. [PMID: 34910319 DOI: 10.1002/jmor.21437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/10/2022]
Abstract
Parrot embryos carry peculiar appendages at their developing beak that have been described as pseudoteeth. To better characterize the pattern of development responsible for the emergence of these dental appendages, we examined parrot embryos combining conventional histology and microtomography approaches. Using immunohistochemistry, we observed the epithelial and mesenchymal expression of several proteins involved in tooth development in mammals. Parrot pseudoteeth arose by epithelial and mesenchymal evagination, and their early development was similar to the ontogeny of scales and feathers. There was no enamel tissue, and the evaginations were surrounded by the rhamphotheca. In adults, the rhamphotheca covers entirely the appendages, now represented by bone evaginations, which were more numerous in the lower than in the upper beak, being similar to the osseous teeth of the fossil Pelagornithidae. These embryonic pseudoteeth resembled reptile's first-generation teeth and dental appendages of chicken talpid2 mutants. Proteins involved in mammalian odontogenesis, such as SHH, BMP4, PITX2, and PAX9, were found to be generally expressed in beak epithelium and mesenchyme during parrot pseudoteeth development, with clusters of high-level expression in the pseudoteeth rudiments. This suggests that a similar, highly conserved gene expression program gives rise to the appearance of odontode derivatives in numerous species, despite their divergent developmental paths. These results provide new insights into the development and evolution of odontode-derived structures in vertebrates.
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Affiliation(s)
- Stéphane Louryan
- Laboratoire d'Anatomie, Biomécanique et Organogenèse (LABO), Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Myriam Choa-Duterre
- Laboratoire d'Anatomie, Biomécanique et Organogenèse (LABO), Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Marie Lejong
- Laboratoire d'Anatomie, Biomécanique et Organogenèse (LABO), Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
| | - Nathalie Vanmuylder
- Laboratoire d'Anatomie, Biomécanique et Organogenèse (LABO), Université Libre de Bruxelles, Faculté de Médecine, Brussels, Belgium
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9
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Palci A, LeBlanc ARH, Panagiotopoulou O, Cleuren SGC, Mehari Abraha H, Hutchinson MN, Evans AR, Caldwell MW, Lee MSY. Plicidentine and the repeated origins of snake venom fangs. Proc Biol Sci 2021; 288:20211391. [PMID: 34375553 PMCID: PMC8354744 DOI: 10.1098/rspb.2021.1391] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 07/19/2021] [Indexed: 12/26/2022] Open
Abstract
Snake fangs are an iconic exemplar of a complex adaptation, but despite striking developmental and morphological similarities, they probably evolved independently in several lineages of venomous snakes. How snakes could, uniquely among vertebrates, repeatedly evolve their complex venom delivery apparatus is an intriguing question. Here we shed light on the repeated evolution of snake venom fangs using histology, high-resolution computed tomography (microCT) and biomechanical modelling. Our examination of venomous and non-venomous species reveals that most snakes have dentine infoldings at the bases of their teeth, known as plicidentine, and that in venomous species, one of these infoldings was repurposed to form a longitudinal groove for venom delivery. Like plicidentine, venom grooves originate from infoldings of the developing dental epithelium prior to the formation of the tooth hard tissues. Derivation of the venom groove from a large plicidentine fold that develops early in tooth ontogeny reveals how snake venom fangs could originate repeatedly through the co-option of a pre-existing dental feature even without close association to a venom duct. We also show that, contrary to previous assumptions, dentine infoldings do not improve compression or bending resistance of snake teeth during biting; plicidentine may instead have a role in tooth attachment.
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Affiliation(s)
- Alessandro Palci
- College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia
- South Australian Museum, North Terrace, Adelaide, SA 5000, Australia
| | - Aaron R. H. LeBlanc
- Department of Biological Sciences, University of Alberta, Edmonton, AB Canada, T6G 2E9
- Faculty of Dentistry, Oral and Craniofacial Sciences, Guy's Campus, King's College London, London WC2R 2LS, UK
| | - Olga Panagiotopoulou
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, VIC 3800, Australia
| | | | - Hyab Mehari Abraha
- Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Faculty of Medicine Nursing and Health Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Mark N. Hutchinson
- College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia
- South Australian Museum, North Terrace, Adelaide, SA 5000, Australia
| | - Alistair R. Evans
- School of Biological Sciences, Monash University, VIC 3800, Australia
- Geosciences, Museums Victoria, Melbourne, VIC 3001, Australia
| | - Michael W. Caldwell
- Department of Biological Sciences, University of Alberta, Edmonton, AB Canada, T6G 2E9
- Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB Canada, T6G 2E9
| | - Michael S. Y. Lee
- College of Science and Engineering, Flinders University, Adelaide, SA 5042, Australia
- South Australian Museum, North Terrace, Adelaide, SA 5000, Australia
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10
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Abramyan J, Geetha-Loganathan P, Šulcová M, Buchtová M. Role of Cell Death in Cellular Processes During Odontogenesis. Front Cell Dev Biol 2021; 9:671475. [PMID: 34222243 PMCID: PMC8250436 DOI: 10.3389/fcell.2021.671475] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 05/24/2021] [Indexed: 01/20/2023] Open
Abstract
The development of a tooth germ in a precise size, shape, and position in the jaw, involves meticulous regulation of cell proliferation and cell death. Apoptosis, as the most common type of programmed cell death during embryonic development, plays a number of key roles during odontogenesis, ranging from the budding of the oral epithelium during tooth initiation, to later tooth germ morphogenesis and removal of enamel knot signaling center. Here, we summarize recent knowledge about the distribution and function of apoptotic cells during odontogenesis in several vertebrate lineages, with a special focus on amniotes (mammals and reptiles). We discuss the regulatory roles that apoptosis plays on various cellular processes during odontogenesis. We also review apoptosis-associated molecular signaling during tooth development, including its relationship with the autophagic pathway. Lastly, we cover apoptotic pathway disruption, and alterations in apoptotic cell distribution in transgenic mouse models. These studies foster a deeper understanding how apoptotic cells affect cellular processes during normal odontogenesis, and how they contribute to dental disorders, which could lead to new avenues of treatment in the future.
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Affiliation(s)
- John Abramyan
- Department of Natural Sciences, University of Michigan–Dearborn, Dearborn, MI, United States
| | | | - Marie Šulcová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czechia
- Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Brno, Czechia
| | - Marcela Buchtová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czechia
- Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Brno, Czechia
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11
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Hovorakova M, Zahradnicek O, Bartos M, Hurnik P, Stransky J, Stembirek J, Tucker AS. Reawakening of Ancestral Dental Potential as a Mechanism to Explain Dental Pathologies. Integr Comp Biol 2021; 60:619-629. [PMID: 32492167 DOI: 10.1093/icb/icaa053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
During evolution, there has been a trend to reduce both the number of teeth and the location where they are found within the oral cavity. In mammals, the formation of teeth is restricted to a horseshoe band of odontogenic tissue, creating a single dental arch on the top and bottom of the jaw. Additional teeth and structures containing dental tissue, such as odontogenic tumors or cysts, can appear as pathologies. These tooth-like structures can be associated with the normal dentition, appearing within the dental arch, or in nondental areas. The etiology of these pathologies is not well elucidated. Reawakening of the potential to form teeth in different parts of the oral cavity could explain the origin of dental pathologies outside the dental arch, thus such pathologies are a consequence of our evolutionary history. In this review, we look at the changing pattern of tooth formation within the oral cavity during vertebrate evolution, the potential to form additional tooth-like structures in mammals, and discuss how this knowledge shapes our understanding of dental pathologies in humans.
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Affiliation(s)
- Maria Hovorakova
- Institute of Histology and Embryology, First Faculty of Medicine, Charles University in Prague, Albertov 4, 128 00 Prague 2, Czech Republic.,Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Oldrich Zahradnicek
- Institute of Experimental Medicine, Czech Academy of Sciences, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Martin Bartos
- Department of Stomatology, First Faculty of Medicine, Charles University, General University Hospital in Prague, Katerinska 32, 12801 Prague 2, Czech Republic.,Institute of Anatomy, First Faculty of Medicine, Charles University, U Nemocnice 3, Prague 2, 128 00, Czech Republic
| | - Pavel Hurnik
- Department of Pathology, University Hospital Ostrava, 17. listopadu 1790, Ostrava-Poruba, 708 52, Czech Republic.,Department of Pathology at Faculty of Medicine, University of Ostrava, Syllabova 19, Ostrava-Zabreh, 703 00, Czech Republic
| | - Jiri Stransky
- Department of Oral and Maxillofacial Surgery, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic
| | - Jan Stembirek
- Department of Oral and Maxillofacial Surgery, University Hospital Ostrava, 17. listopadu 1790, 708 52 Ostrava-Poruba, Czech Republic.,Institute of Animal Physiology and Genetics, v.v.i., Czech Academy of Sciences, Veveri 97, 602 00, Brno 2, Czech Republic
| | - Abigail S Tucker
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, UK
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12
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Hermyt M, Metscher B, Rupik W. Ultrastructural studies of developing egg tooth in grass snake Natrix natrix (Squamata, Serpentes) embryos, supported by X-ray microtomography analysis. ZOOLOGY 2021; 146:125913. [PMID: 33765551 DOI: 10.1016/j.zool.2021.125913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 10/22/2022]
Abstract
The egg tooth development is similar to the development of all the other vertebrate teeth except earliest developmental stages because the egg tooth develops directly from the oral epithelium instead of the dental lamina similarly to null generation teeth. The developing egg tooth of Natrix natrix changes its curvature differently than the egg tooth of the other investigated unidentates due to the presence of the rostral groove. The developing grass snake egg tooth comprises dental pulp and the enamel organ. The fully differentiated enamel organ consists of outer enamel epithelium, stellate reticulum, and ameloblasts in its inner layer. The enamel organ directly in contact with the oral cavity is covered with periderm instead of outer enamel epithelium. Stellate reticulum cells in the grass snake egg tooth share intercellular spaces with the basal part of ameloblasts and are responsible for their nutrition. Ameloblasts during egg tooth differentiation pass through the following stages: presecretory, secretory, and mature. The ameloblasts from the grass snake egg tooth show the same cellular changes as reported during mammalian amelogenesis but are devoid of Tomes' processes. Odontoblasts of the developing grass snake egg tooth pass through the following classes: pre-odontoblasts, secretory odontoblasts, and ageing odontoblasts. They have highly differentiated secretory apparatus and in the course of their activity accumulate lipofuscin. Grass snake odontoblasts possess processes which are poor in organelles. In developing egg tooth cilia have been identified in odontoblasts, ameloblasts and cells of the stellate reticulum. Dental pulp cells remodel collagen matrix during growth of the grass snake egg tooth. They degenerate in a way previously not described in other teeth.
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Affiliation(s)
- Mateusz Hermyt
- University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, 9 Bankowa Str., 40-007, Katowice, Poland
| | - Brian Metscher
- Department of Evolutionary Biology, University of Vienna, Althanstraße 14, 1090, Austria
| | - Weronika Rupik
- University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, 9 Bankowa Str., 40-007, Katowice, Poland.
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13
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LeBlanc ARH, Paparella I, Lamoureux DO, Doschak MR, Caldwell MW. Tooth attachment and pleurodont implantation in lizards: Histology, development, and evolution. J Anat 2020; 238:1156-1178. [PMID: 33372719 PMCID: PMC8053593 DOI: 10.1111/joa.13371] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/10/2020] [Accepted: 11/10/2020] [Indexed: 01/13/2023] Open
Abstract
Squamates present a unique challenge to the homology and evolution of tooth attachment tissues. Their stereotypically pleurodont teeth are fused in place by a single "bone of attachment", with seemingly dubious homology to the three-part tooth attachment system of mammals and crocodilians. Despite extensive debate over the interpretations of squamate pleurodonty, its phylogenetic significance, and the growing evidence from fossil amniotes for the homology of tooth attachment tissues, few studies have defined pleurodonty on histological grounds. Using a sample of extant squamate teeth that we organize into three broad categories of implantation, we investigate the histological and developmental properties of their dental tissues in multiple planes of section. We use these data to demonstrate the specific soft- and hard-tissue features of squamate teeth that produce their disparate tooth implantation modes. In addition, we describe cementum, periodontal ligaments, and alveolar bone in pleurodont squamates, dental tissues that were historically thought to be restricted to extant mammals and crocodilians. Moreover, we show how the differences between pleurodonty and thecodonty do not relate to the identity of the tooth attachment tissues, but rather the arrangements of homologous tissues around the teeth.
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Affiliation(s)
- Aaron R H LeBlanc
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Ilaria Paparella
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | | | - Michael R Doschak
- Faculty of Pharmacy & Pharmaceutical Sciences and Department of Biomedical Engineering, University of Alberta, Edmonton, AB, Canada
| | - Michael W Caldwell
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.,Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada
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14
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Kavková M, Šulcová M, Dumková J, Zahradníček O, Kaiser J, Tucker AS, Zikmund T, Buchtová M. Coordinated labio-lingual asymmetries in dental and bone development create a symmetrical acrodont dentition. Sci Rep 2020; 10:22040. [PMID: 33328503 PMCID: PMC7745041 DOI: 10.1038/s41598-020-78939-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 11/26/2020] [Indexed: 11/09/2022] Open
Abstract
Organs throughout the body develop both asymmetrically and symmetrically. Here, we assess how symmetrical teeth in reptiles can be created from asymmetrical tooth germs. Teeth of lepidosaurian reptiles are mostly anchored to the jaw bones by pleurodont ankylosis, where the tooth is held in place on the labial side only. Pleurodont teeth are characterized by significantly asymmetrical development of the labial and lingual sides of the cervical loop, which later leads to uneven deposition of hard tissue. On the other hand, acrodont teeth found in lizards of the Acrodonta clade (i.e. agamas, chameleons) are symmetrically ankylosed to the jaw bone. Here, we have focused on the formation of the symmetrical acrodont dentition of the veiled chameleon (Chamaeleo calyptratus). Intriguingly, our results revealed distinct asymmetries in morphology of the labial and lingual sides of the cervical loop during early developmental stages, both at the gross and ultrastructural level, with specific patterns of cell proliferation and stem cell marker expression. Asymmetrical expression of ST14 was also observed, with a positive domain on the lingual side of the cervical loop overlapping with the SOX2 domain. In contrast, micro-CT analysis of hard tissues revealed that deposition of dentin and enamel was largely symmetrical at the mineralization stage, highlighting the difference between cervical loop morphology during early development and differentiation of odontoblasts throughout later odontogenesis. In conclusion, the early asymmetrical development of the enamel organ seems to be a plesiomorphic character for all squamate reptiles, while symmetrical and precisely orchestrated deposition of hard tissue during tooth formation in acrodont dentitions probably represents a novelty in the Acrodonta clade.
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Affiliation(s)
- M Kavková
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - M Šulcová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.,Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Veveri 97, 602 00, Brno, Czech Republic
| | - J Dumková
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - O Zahradníček
- Department of Radiation Dosimetry, Nuclear Physics Institute, Czech Academy of Sciences, Prague, Czech Republic
| | - J Kaiser
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - A S Tucker
- Centre for Craniofacial and Regenerative Biology, King's College London, Floor 27 Guy's Tower, Guy's Hospital, London Bridge, London, UK
| | - T Zikmund
- Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic
| | - M Buchtová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic. .,Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Veveri 97, 602 00, Brno, Czech Republic.
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15
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Hermyt M, Metscher B, Rupik W. Do all geckos hatch in the same way? Histological and
3D
studies of egg tooth morphogenesis in the geckos
Eublepharis macularius
Blyth 1854 and
Lepidodactylus lugubris
Duméril & Bibron 1836. J Morphol 2020; 281:1313-1327. [DOI: 10.1002/jmor.21249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 07/08/2020] [Accepted: 07/22/2020] [Indexed: 02/06/2023]
Affiliation(s)
- Mateusz Hermyt
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection University of Silesia in Katowice Katowice Poland
| | - Brian Metscher
- Department of Evolutionary Biology University of Vienna Vienna Austria
| | - Weronika Rupik
- Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection University of Silesia in Katowice Katowice Poland
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16
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Anthwal N, Fenelon JC, Johnston SD, Renfree MB, Tucker AS. Transient role of the middle ear as a lower jaw support across mammals. eLife 2020; 9:e57860. [PMID: 32600529 PMCID: PMC7363448 DOI: 10.7554/elife.57860] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022] Open
Abstract
Mammals articulate their jaws using a novel joint between the dentary and squamosal bones. In eutherian mammals, this joint forms in the embryo, supporting feeding and vocalisation from birth. In contrast, marsupials and monotremes exhibit extreme altriciality and are born before the bones of the novel mammalian jaw joint form. These mammals need to rely on other mechanisms to allow them to feed. Here, we show that this vital function is carried out by the earlier developing, cartilaginous incus of the middle ear, abutting the cranial base to form a cranio-mandibular articulation. The nature of this articulation varies between monotremes and marsupials, with juvenile monotremes retaining a double articulation, similar to that of the fossil mammaliaform Morganucodon, while marsupials use a versican-rich matrix to stabilise the jaw against the cranial base. These findings provide novel insight into the evolution of mammals and the changing relationship between the jaw and ear.
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Affiliation(s)
- Neal Anthwal
- Centre for Craniofacial and Regenerative Biology, King's College LondonLondonUnited Kingdom
| | - Jane C Fenelon
- School of BioSciences, University of MelbourneVictoriaAustralia
| | - Stephen D Johnston
- School of Agriculture and Food Sciences, University of QueenslandGattonAustralia
| | | | - Abigail S Tucker
- Centre for Craniofacial and Regenerative Biology, King's College LondonLondonUnited Kingdom
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17
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Hermyt M, Janiszewska K, Rupik W. Squamate egg tooth development revisited using three-dimensional reconstructions of brown anole (Anolis sagrei, Squamata, Dactyloidae) dentition. J Anat 2020; 236:1004-1020. [PMID: 32056203 PMCID: PMC7219623 DOI: 10.1111/joa.13166] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 01/17/2020] [Accepted: 01/20/2020] [Indexed: 02/02/2023] Open
Abstract
The egg tooth is a hatching adaptation, characteristic of all squamates. In brown anole embryos, the first tooth that starts differentiating is the egg tooth. It develops from a single tooth germ and, similar to the regular dentition of all the other vertebrates, the differentiating egg tooth of the brown anole passes through classic morphological and developmental stages named according to the shape of the dental epithelium: epithelial thickening, dental lamina, tooth bud, cap and bell stages. The differentiating egg tooth consists of three parts: the enamel organ, hard tissues and dental pulp. Shortly before hatching, the egg tooth connects with the premaxilla. Attachment tissue of the egg tooth does not undergo mineralization, which makes it different from the other teeth of most squamates. After hatching, odontoclasts are involved in resorption of the egg tooth's remains. This study shows that the brown anole egg tooth does not completely conform to previous reports describing iguanomorph egg teeth and reveals a need to investigate its development in the context of squamate phylogeny.
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Affiliation(s)
- Mateusz Hermyt
- Faculty of Natural SciencesInstitute of Biology, Biotechnology and Environmental ProtectionUniversity of Silesia in KatowiceKatowicePoland
| | | | - Weronika Rupik
- Faculty of Natural SciencesInstitute of Biology, Biotechnology and Environmental ProtectionUniversity of Silesia in KatowiceKatowicePoland
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18
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Sadier A, Jackman WR, Laudet V, Gibert Y. The Vertebrate Tooth Row: Is It Initiated by a Single Organizing Tooth? Bioessays 2020; 42:e1900229. [PMID: 32347985 DOI: 10.1002/bies.201900229] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/20/2020] [Indexed: 01/10/2023]
Abstract
Teeth are one of the most fascinating innovations of vertebrates. Their diversity of shape, size, location, and number in vertebrates is astonishing. If the molecular mechanisms underlying the morphogenesis of individual teeth are now relatively well understood, thanks to the detailed experimental work that has been performed in model organisms (mainly mouse and zebrafish), the mechanisms that control the organization of the dentition are still a mystery. Mammals display simplified dentitions when compared to other vertebrates with only a single tooth row positioned in the anterior part of the mouth, whereas other vertebrates exhibit tooth rows in many locations. As proposed 60 years ago, tooth rows can be formed sequentially from an initiator tooth. Recent results in zebrafish have now largely confirmed this hypothesis. Here this observation is generalized upon and it is suggested that in most vertebrates tooth rows could form sequentially from a single initiator tooth.
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Affiliation(s)
- Alexa Sadier
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, 90095, USA
| | | | - Vincent Laudet
- Observatoire Océanologique de Banyuls-sur-Mer, UMR CNRS 7232 BIOM, Sorbonne Université Paris, 1, avenue Pierre Fabre, Banyuls-sur-Mer, 66650, France
| | - Yann Gibert
- University of Mississippi Medical Center, Department of Cell and Molecular Biology, 2500 North State Street, Jackson, MS, 39216, USA
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19
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Chapelle KEJ, Fernandez V, Choiniere JN. Conserved in-ovo cranial ossification sequences of extant saurians allow estimation of embryonic dinosaur developmental stages. Sci Rep 2020; 10:4224. [PMID: 32273522 PMCID: PMC7145871 DOI: 10.1038/s41598-020-60292-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 01/30/2020] [Indexed: 11/23/2022] Open
Abstract
Dinosaur embryos are among the rarest of fossils, yet they provide a unique window into the palaeobiology of these animals. Estimating the developmental stage of dinosaur embryos is hindered by the lack of a quantitative method for age determination, by the scarcity of material, and by the difficulty in visualizing that material. Here we present the results of a broad inquiry, using 3D reconstructions from X-ray computed tomography data, into cranial ossification sequences in extant saurian taxa and in well-preserved embryos of the early branching sauropodomorph dinosaur Massospondylus carinatus. Our findings support deep-time conservation of cranial ossification sequences in saurians including dinosaurs, allowing us to develop a new method for estimating the relative developmental percentage of embryos from that clade. We also observe null-generation teeth in the Massospondylus carinatus embryos which get resorbed or shed before hatching, similar to those of geckos. These lines of evidence allow us to confidently estimate that the Massospondylus carinatus embryos are only approximately 60% through their incubation period, much younger than previously hypothesized. The overall consistency of our results with those of living saurians indicates that they can be generalized to other extinct members of that lineage, and therefore our method provides an independent means of assessing the developmental stage of extinct, in-ovo saurians.
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Affiliation(s)
- Kimberley E J Chapelle
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, Gauteng, South Africa.
- School of Geosciences, University of the Witwatersrand, Johannesburg, Gauteng, South Africa.
| | - Vincent Fernandez
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
- European Synchrotron Radiation Facility, Grenoble, France
- Imaging and Analysis Centre, Natural History Museum, London, United Kingdom
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
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20
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Landova Sulcova M, Zahradnicek O, Dumkova J, Dosedelova H, Krivanek J, Hampl M, Kavkova M, Zikmund T, Gregorovicova M, Sedmera D, Kaiser J, Tucker AS, Buchtova M. Developmental mechanisms driving complex tooth shape in reptiles. Dev Dyn 2020; 249:441-464. [DOI: 10.1002/dvdy.138] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 11/03/2019] [Accepted: 11/18/2019] [Indexed: 12/20/2022] Open
Affiliation(s)
- Marie Landova Sulcova
- Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and GeneticsCzech Academy of Science Brno Czech Republic
- Department of Experimental Biology, Faculty of ScienceMasaryk University Brno Czech Republic
| | - Oldrich Zahradnicek
- Institute of Experimental MedicineCzech Academy of Science Prague Czech Republic
| | - Jana Dumkova
- Department of Histology and EmbryologyFaculty of Medicine, Masaryk University Brno Czech Republic
| | - Hana Dosedelova
- Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and GeneticsCzech Academy of Science Brno Czech Republic
| | - Jan Krivanek
- Department of Histology and EmbryologyFaculty of Medicine, Masaryk University Brno Czech Republic
| | - Marek Hampl
- Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and GeneticsCzech Academy of Science Brno Czech Republic
- Department of Experimental Biology, Faculty of ScienceMasaryk University Brno Czech Republic
| | - Michaela Kavkova
- CEITEC‐Central European Institute of TechnologyUniversity of Technology Brno Czech Republic
| | - Tomas Zikmund
- CEITEC‐Central European Institute of TechnologyUniversity of Technology Brno Czech Republic
| | - Martina Gregorovicova
- Institute of Anatomy, Medical FacultyCharles University Prague Czech Republic
- Institute of PhysiologyCzech Academy of Sciences Prague Czech Republic
| | - David Sedmera
- Institute of Anatomy, Medical FacultyCharles University Prague Czech Republic
- Institute of PhysiologyCzech Academy of Sciences Prague Czech Republic
| | - Jozef Kaiser
- CEITEC‐Central European Institute of TechnologyUniversity of Technology Brno Czech Republic
| | - Abigail S. Tucker
- Institute of Experimental MedicineCzech Academy of Science Prague Czech Republic
- Centre for Craniofacial and Regenerative BiologyFaculty of Dentistry, Oral and Craniofacial Sciences, King's College London London UK
| | - Marcela Buchtova
- Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and GeneticsCzech Academy of Science Brno Czech Republic
- Department of Experimental Biology, Faculty of ScienceMasaryk University Brno Czech Republic
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21
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Jones MEH, Lucas PW, Tucker AS, Watson AP, Sertich JJW, Foster JR, Williams R, Garbe U, Bevitt JJ, Salvemini F. Neutron scanning reveals unexpected complexity in the enamel thickness of an herbivorous Jurassic reptile. J R Soc Interface 2019; 15:rsif.2018.0039. [PMID: 29899156 PMCID: PMC6030635 DOI: 10.1098/rsif.2018.0039] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/18/2018] [Indexed: 11/12/2022] Open
Abstract
Eilenodontines are one of the oldest radiation of herbivorous lepidosaurs (snakes, lizards and tuatara) characterized by batteries of wide teeth with thick enamel that bear mammal-like wear facets. Unlike most reptiles, eilenodontines have limited tooth replacement, making dental longevity particularly important to them. We use both X-ray and neutron computed tomography to examine a fossil tooth from the eilenodontine Eilenodon (Late Jurassic, USA). Of the two approaches, neutron tomography was more successful and facilitated measurements of enamel thickness and distribution. We find the enamel thickness to be regionally variable, thin near the cusp tip (0.10 mm) but thicker around the base (0.15–0.30 mm) and notably greater than that of other rhynchocephalians such as the extant Sphenodon (0.08–0.14 mm). The thick enamel in Eilenodon would permit greater loading, extend tooth lifespan and facilitate the establishment of wear facets that have sharp edges for orally processing plant material such as horsetails (Equisetum). The shape of the enamel dentine junction indicates that tooth development in Eilenodon and Sphenodon involved similar folding of the epithelium but different ameloblast activity.
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Affiliation(s)
- Marc E H Jones
- Department of Earth Sciences, The Natural History Museum, London, UK .,Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia.,South Australian Museum, North Terrace, Adelaide, South Australia 5001, Australia
| | - Peter W Lucas
- Smithsonian Tropical Research Institute, Balboa, Panama
| | - Abigail S Tucker
- Craniofacial Development and Stem Cell Biology, King's College London, London, UK
| | - Amy P Watson
- Department of Genetics and Evolution, School of Biological Sciences, The University of Adelaide, North Terrace, Adelaide, South Australia 5005, Australia
| | - Joseph J W Sertich
- Department of Earth Sciences, Denver Museum of Nature and Science, Denver, CO, USA
| | | | - Ruth Williams
- Department of Adelaide Microscopy, The University of Adelaide, Adelaide, South Australia 5001, Australia
| | - Ulf Garbe
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | - Joseph J Bevitt
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, Australia
| | - Floriana Salvemini
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Sydney, Australia
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22
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Button K, You H, Kirkland JI, Zanno L. Incremental growth of therizinosaurian dental tissues: implications for dietary transitions in Theropoda. PeerJ 2017; 5:e4129. [PMID: 29250467 PMCID: PMC5729821 DOI: 10.7717/peerj.4129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/14/2017] [Indexed: 11/20/2022] Open
Abstract
Previous investigations document functional and phylogenetic signals in the histology of dinosaur teeth. In particular, incremental lines in dentin have been used to determine tooth growth and replacement rates in several dinosaurian clades. However, to date, few studies have investigated the dental microstructure of theropods in the omnivory/herbivory spectrum. Here we examine dental histology of Therizinosauria, a clade of large-bodied theropods bearing significant morphological evidence for herbivory, by examining the teeth of the early-diverging therizinosaurian Falcarius utahensis, and an isolated tooth referred to Suzhousaurus megatherioides, a highly specialized large-bodied representative. Despite attaining some of the largest body masses among maniraptoran theropod dinosaurs, therizinosaurian teeth are diminutive, measuring no more than 0.90 cm in crown height (CH) and 0.38 cm in crown base length (CBL). Comparisons with other theropods and non-theropodan herbivorous dinosaurs reveals that when controlling for estimated body mass, crown volume in therizinosaurians plots most closely with dinosaurs of similar dietary strategy as opposed to phylogenetic heritage. Analysis of incremental growth lines in dentin, observed in thin sections of therizinosaurian teeth, demonstrates that tooth growth rates fall within the range of other archosaurs, conforming to hypothesized physiological limitations on the production of dental tissues. Despite dietary differences between therizinosaurians and hypercarnivorous theropods, the types of enamel crystallites present and their spatial distribution—i.e., the schmelzmuster of both taxa—is limited to parallel enamel crystallites, the simplest form of enamel and the plesiomorphic condition for Theropoda. This finding supports previous hypotheses that dental microstructure is strongly influenced by phylogeny, yet equally supports suggestions of reduced reliance on oral processing in omnivorous/herbivorous theropods rather than the microstructural specializations to diet exhibited by non-theropodan herbivorous dinosaurs. Finally, although our sample is limited, we document a significant reduction in the rate of enamel apposition contrasted with increased relative enamel thickness between early and later diverging therizinosaurians that coincides with anatomical evidence for increased specializations to herbivory in the clade.
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Affiliation(s)
- Khai Button
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America.,Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, United States of America
| | - Hailu You
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China.,College of Earth Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - James I Kirkland
- Utah Geological Survey, Salt Lake City, UT, United States of America
| | - Lindsay Zanno
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, United States of America.,Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC, United States of America
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23
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Kubička L, Schořálková T, Červenka J, Kratochvíl L. Ovarian control of growth and sexual size dimorphism in a male-larger gecko. ACTA ACUST UNITED AC 2017; 220:787-795. [PMID: 27956485 DOI: 10.1242/jeb.146597] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 12/07/2016] [Indexed: 11/20/2022]
Abstract
Sexual size dimorphism (SSD) reflects sex-specific solutions to the allocation of energy among growth, reproduction and survival; however, the proximate mechanisms behind these solutions are still poorly known even in vertebrates. In squamates, sexual differences in body size used to be attributed to direct energy allocation to energetically demanding processes, largely to reproduction. In addition, SSD is assumed to be controlled by specific endogenous mechanisms regulating growth in a sex-specific manner, namely masculinization by male gonadal androgens or feminization by ovarian hormones. We performed a manipulative growth experiment in females of the male-larger gecko Paroedura picta in order to test the reproductive cost hypothesis, the male androgen hypothesis and the ovarian hormone hypothesis. Specifically, we investigated the effect of total ovariectomy, prepubertal ovariectomy, unilateral ovariectomy, and total ovariectomy followed by exogenous estradiol, dihydrotestosterone or testosterone treatment, on female growth in comparison to males and reproductively active females. The present results and the results of our previous experiments do not support the hypotheses that SSD reflects direct energy allocation to reproduction and that male gonadal androgens are involved. However, all lines of evidence, particularly the comparable growth of reproducing intact and unilaterally ovariectomized females, were concordant with the control of SSD by ovarian hormones. We suggest that feminization of growth by female gonadal hormones should be taken into consideration as an endogenous pathway responsible for the ontogeny of SSD in squamates.
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Affiliation(s)
- Lukáš Kubička
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Praha 2 128 44, Czech Republic
| | - Tereza Schořálková
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Praha 2 128 44, Czech Republic
| | - Jan Červenka
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Praha 2 128 44, Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Praha 2 128 44, Czech Republic
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24
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Erickson GM, Zelenitsky DK, Kay DI, Norell MA. Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development. Proc Natl Acad Sci U S A 2017; 114:540-545. [PMID: 28049837 PMCID: PMC5255600 DOI: 10.1073/pnas.1613716114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Birds stand out from other egg-laying amniotes by producing relatively small numbers of large eggs with very short incubation periods (average 11-85 d). This aspect promotes high survivorship by limiting exposure to predation and environmental perturbation, allows for larger more fit young, and facilitates rapid attainment of adult size. Birds are living dinosaurs; their rapid development has been considered to reflect the primitive dinosaurian condition. Here, nonavian dinosaurian incubation periods in both small and large ornithischian taxa are empirically determined through growth-line counts in embryonic teeth. Our results show unexpectedly slow incubation (2.8 and 5.8 mo) like those of outgroup reptiles. Developmental and physiological constraints would have rendered tooth formation and incubation inherently slow in other dinosaur lineages and basal birds. The capacity to determine incubation periods in extinct egg-laying amniotes has implications for dinosaurian embryology, life history strategies, and survivorship across the Cretaceous-Paleogene mass extinction event.
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Affiliation(s)
- Gregory M Erickson
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295;
| | - Darla K Zelenitsky
- Department of Geoscience, University of Calgary, Calgary, AB, Canada T2N 1N4
| | - David Ian Kay
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295
| | - Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, NY 10024
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25
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Hermyt M, Kaczmarek P, Kowalska M, Rupik W. Development of the egg tooth – The tool facilitating hatching of squamates: Lessons from the grass snake Natrix natrix. ZOOL ANZ 2017. [DOI: 10.1016/j.jcz.2016.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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26
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Popa EM, Anthwal N, Tucker AS. Complex patterns of tooth replacement revealed in the fruit bat (Eidolon helvum). J Anat 2016; 229:847-856. [PMID: 27444818 DOI: 10.1111/joa.12522] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2016] [Indexed: 12/17/2022] Open
Abstract
How teeth are replaced during normal growth and development has long been an important question for comparative and developmental anatomy. Non-standard model animals have become increasingly popular in this field due to the fact that the canonical model laboratory mammal, the mouse, develops only one generation of teeth (monophyodonty), whereas the majority of mammals possess two generations of teeth (diphyodonty). Here we used the straw-coloured fruit bat (Eidolon helvum), an Old World megabat, which has two generations of teeth, in order to observe the development and replacement of tooth germs from initiation up to mineralization stages. Our morphological study uses 3D reconstruction of histological sections to uncover differing arrangements of the first and second-generation tooth germs during the process of tooth replacement. We show that both tooth germ generations develop as part of the dental lamina, with the first generation detaching from the lamina, leaving the free edge to give rise to a second generation. This separation was particularly marked at the third premolar locus, where the primary and replacement teeth become positioned side by side, unconnected by a lamina. The position of the replacement tooth, with respect to the primary tooth, varied within the mouth, with replacements forming posterior to or directly lingual to the primary tooth. Development of replacement teeth was arrested at some tooth positions and this appeared to be linked to the timing of tooth initiation and the subsequent rate of development. This study adds an additional species to the growing body of non-model species used in the study of tooth replacement, and offers a new insight into the development of the diphyodont condition.
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Affiliation(s)
- Elena M Popa
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Hospital, London, UK
| | - Neal Anthwal
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Hospital, London, UK
| | - Abigail S Tucker
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Hospital, London, UK
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27
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Starostová Z, Musilová Z. The complete mitochondrial genome of the Madagascar ground gecko Paroedura picta (Squamata: Gekkonidae). Mitochondrial DNA A DNA Mapp Seq Anal 2015; 27:4397-4398. [PMID: 26477699 DOI: 10.3109/19401736.2015.1089540] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We sequenced the complete mitochondrial genome of the Madagascar ground gecko Paroedura picta (Squamata: Gekkonidae). The mitogenome is 17 220 base pairs long and conforms to the typical vertebrate gene composition and arrangement, i.e. 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes and 1919 bp long control region. We reconstructed phylogenetic relationships of P. picta and representatives of nine other genera from the family Gekkonidae and calculated mean p-distances for all 13 protein-coding mitochondrial genes. The lowest mean p-distances were found in cytochrome oxidase subunit I and III genes (COI and COIII) indicating their usefulness for elucidating deeper phylogenetic relationships.
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Affiliation(s)
- Zuzana Starostová
- a Department of Zoology , Faculty of Science, Charles University in Prague , Viničná, Prague , Czech Republic and
| | - Zuzana Musilová
- a Department of Zoology , Faculty of Science, Charles University in Prague , Viničná, Prague , Czech Republic and.,b Zoological Institute, University of Basel , Basel , Switzerland
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28
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Dosedělová H, Dumková J, Lesot H, Glocová K, Kunová M, Tucker AS, Veselá I, Krejčí P, Tichý F, Hampl A, Buchtová M. Fate of the molar dental lamina in the monophyodont mouse. PLoS One 2015; 10:e0127543. [PMID: 26010446 PMCID: PMC4444311 DOI: 10.1371/journal.pone.0127543] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 04/16/2015] [Indexed: 11/19/2022] Open
Abstract
The successional dental lamina (SDL) plays an essential role in the development of replacement teeth in diphyodont and polyphyodont animals. A morphologically similar structure, the rudimental successional dental lamina (RSDL), has been described in monophyodont (only one tooth generation) lizards on the lingual side of the developing functional tooth. This rudimentary lamina regresses, which has been proposed to play a role in preventing the formation of future generations of teeth. A similar rudimentary lingual structure has been reported associated with the first molar in the monophyodont mouse, and we show that this structure is common to all murine molars. Intriguingly, a lingual lamina is also observed on the non-replacing molars of other diphyodont mammals (pig and hedgehog), initially appearing very similar to the successional dental lamina on the replacing teeth. We have analyzed the morphological as well as ultrastructural changes that occur during the development and loss of this molar lamina in the mouse, from its initiation at late embryonic stages to its disappearance at postnatal stages. We show that loss appears to be driven by a reduction in cell proliferation, down-regulation of the progenitor marker Sox2, with only a small number of cells undergoing programmed cell death. The lingual lamina was associated with the dental stalk, a short epithelial connection between the tooth germ and the oral epithelium. The dental stalk remained in contact with the oral epithelium throughout tooth development up to eruption when connective tissue and numerous capillaries progressively invaded the dental stalk. The buccal side of the dental stalk underwent keratinisation and became part of the gingival epithelium, while most of the lingual cells underwent programmed cell death and the tissue directly above the erupting tooth was shed into the oral cavity.
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Affiliation(s)
- Hana Dosedělová
- Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
- Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | - Jana Dumková
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Hervé Lesot
- INSERM UMR1109, Team "Osteoarticular and Dental Regenerative NanoMedicine", Université de Strasbourg, Strasbourg, France
- Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France
| | - Kristýna Glocová
- Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
| | - Michaela Kunová
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Abigail S. Tucker
- Department of Craniofacial Development and Stem Cell Biology, King´s College London, London, United Kingdom
- Department of Orthodontics, King´s College London Dental Institute, London, United Kingdom
| | - Iva Veselá
- Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
- Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | - Pavel Krejčí
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - František Tichý
- Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
| | - Aleš Hampl
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Marcela Buchtová
- Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
- Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech Republic, Brno, Czech Republic
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
- * E-mail:
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29
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Khannoon ER, Russell AP, Tucker AS. Developmental mechanisms underlying differential claw expression in the autopodia of geckos. EvoDevo 2015; 6:8. [PMID: 25878768 PMCID: PMC4397723 DOI: 10.1186/s13227-015-0003-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 03/11/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The limb and autopodium are frequently employed to study pattern formation during embryonic development, providing insights into how cells give rise to complex anatomical structures. With regard to the differentiation of structures at the distal tips of digits, geckos constitute an attractive clade, because within their ranks they exhibit multiple independent occurrences of claw loss and reduction, these being linked to the development of adhesive pads. The developmental patterns that lead to claw loss, however, remain undescribed. Among geckos, Tarentola is a genus characterized by large claws on digits III and IV of the manus and pes, with digits I, II, and V bearing only vestigial claws, or lacking them entirely. The variable expression of claws on different digits provides the opportunity to investigate the processes leading to claw reduction and loss within a single species. RESULTS Here, we document the embryonic developmental dynamics that lead to this intraspecifically variable pattern, focusing on the cellular processes of proliferation and cell death. We find that claws initially develop on all digits of all autopodia, but, later in development, those of digits I, II, and V regress, leading to the adult condition in which robust claws are evident only on digits III and IV. Early apoptotic activity at the digit tips, followed by apoptosis of the claw primordium, premature ossification of the terminal phalanges, and later differential proliferative activity are collectively responsible for claw regression in particular digits. CONCLUSIONS Claw reduction and loss in Tarentola result from differential intensities of apoptosis and cellular proliferation in different digits, and these processes have already had some effect before visible signs of claw development are evident. The differential processes persist through later developmental stages. Variable expression of iteratively homologous structures between digits within autopodia makes claw reduction and loss in Tarentola an excellent vehicle for exploring the developmental mechanisms that lead to evolutionary reduction and loss of structures.
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Affiliation(s)
- Eraqi R Khannoon
- Zoology Department, Faculty of Science, Fayoum University, Fayoum, 63514 Egypt ; King's College London, Floor 27 Guy's Tower, Guy's Hospital, Great Maze Pond, London Bridge, London, SE1 9RT UK
| | - Anthony P Russell
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4 Canada
| | - Abigail S Tucker
- King's College London, Floor 27 Guy's Tower, Guy's Hospital, Great Maze Pond, London Bridge, London, SE1 9RT UK
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30
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Zahradnicek O, Buchtova M, Dosedelova H, Tucker AS. The development of complex tooth shape in reptiles. Front Physiol 2014; 5:74. [PMID: 24611053 PMCID: PMC3933779 DOI: 10.3389/fphys.2014.00074] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 02/06/2014] [Indexed: 11/13/2022] Open
Abstract
Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development.
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Affiliation(s)
- Oldrich Zahradnicek
- Department of Teratology, Institute of Experimental Medicine, v.v.i., Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | - Marcela Buchtova
- Laboratory of Animal Embryology, Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech RepublicBrno, Czech Republic
- Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical SciencesBrno, Czech Republic
| | - Hana Dosedelova
- Laboratory of Animal Embryology, Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech RepublicBrno, Czech Republic
- Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical SciencesBrno, Czech Republic
| | - Abigail S. Tucker
- Department of Craniofacial Development and Stem Cell Biology, and Department of Orthodontics, King's College London, Guy's HospitalLondon, UK
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31
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Tucker AS, Fraser GJ. Evolution and developmental diversity of tooth regeneration. Semin Cell Dev Biol 2014; 25-26:71-80. [PMID: 24406627 DOI: 10.1016/j.semcdb.2013.12.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 12/19/2013] [Accepted: 12/19/2013] [Indexed: 02/06/2023]
Abstract
This review considers the diversity observed during both the development and evolution of tooth replacement throughout the vertebrates in a phylogenetic framework from basal extant chondrichthyan fish and more derived teleost fish to mammals. We illustrate the conservation of the tooth regeneration process among vertebrate clades, where tooth regeneration refers to multiple tooth successors formed de novo for each tooth position in the jaws from a common set of retained dental progenitor cells. We discuss the conserved genetic mechanisms that might be modified to promote morphological diversity in replacement dentitions. We review current research and recent progress in this field during the last decade that have promoted our understanding of tooth diversity in an evolutionary developmental context, and show how tooth replacement and dental regeneration have impacted the evolution of the tooth-jaw module in vertebrates.
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Affiliation(s)
- Abigail S Tucker
- Department of Craniofacial Development and Stem Cell Biology, Floor 27 Guy's Tower, Guys Campus, King's College London, SE1 9RT, UK.
| | - Gareth J Fraser
- Department of Animal and Plant Sciences, Alfred Denny Building, Western Bank, University of Sheffield, S10 2TN, UK.
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32
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Zahradnicek O, Buchtova M, Dosedelova H, Tucker AS. The development of complex tooth shape in reptiles. Front Physiol 2014. [PMID: 24611053 DOI: 10.3389/phys.2014.00074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
Reptiles have a diverse array of tooth shapes, from simple unicuspid to complex multicuspid teeth, reflecting functional adaptation to a variety of diets and eating styles. In addition to cusps, often complex longitudinal labial and lingual enamel crests are widespread and contribute to the final shape of reptile teeth. The simplest shaped unicuspid teeth have been found in piscivorous or carnivorous ancestors of recent diapsid reptiles and they are also present in some extant carnivores such as crocodiles and snakes. However, the ancestral tooth shape for squamate reptiles is thought to be bicuspid, indicating an insectivorous diet. The development of bicuspid teeth in lizards has recently been published, indicating that the mechanisms used to create cusps and crests are very distinct from those that shape cusps in mammals. Here, we introduce the large variety of tooth shapes found in lizards and compare the morphology and development of bicuspid, tricuspid, and pentacuspid teeth, with the aim of understanding how such tooth shapes are generated. Next, we discuss whether the processes used to form such morphologies are conserved between divergent lizards and whether the underlying mechanisms share similarities with those of mammals. In particular, we will focus on the complex teeth of the chameleon, gecko, varanus, and anole lizards using SEM and histology to compare the tooth crown morphology and embryonic development.
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Affiliation(s)
- Oldrich Zahradnicek
- Department of Teratology, Institute of Experimental Medicine, v.v.i., Academy of Sciences of the Czech Republic Prague, Czech Republic
| | - Marcela Buchtova
- Laboratory of Animal Embryology, Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech Republic Brno, Czech Republic ; Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic
| | - Hana Dosedelova
- Laboratory of Animal Embryology, Institute of Animal Physiology and Genetics, v.v.i., Academy of Sciences of the Czech Republic Brno, Czech Republic ; Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic
| | - Abigail S Tucker
- Department of Craniofacial Development and Stem Cell Biology, and Department of Orthodontics, King's College London, Guy's Hospital London, UK
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Buchtová M, Zahradníček O, Balková S, Tucker AS. Odontogenesis in the Veiled Chameleon (Chamaeleo calyptratus). Arch Oral Biol 2013. [DOI: 10.1016/j.archoralbio.2012.10.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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