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Salomies L, Eymann J, Ollonen J, Khan I, Di-Poï N. The developmental origins of heterodonty and acrodonty as revealed by reptile dentitions. SCIENCE ADVANCES 2021; 7:eabj7912. [PMID: 34919438 PMCID: PMC8682985 DOI: 10.1126/sciadv.abj7912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 11/01/2021] [Indexed: 06/14/2023]
Abstract
Despite the exceptional diversity and central role of dentitions in vertebrate evolution, many aspects of tooth characters remain unknown. Here, we exploit the large array of dental phenotypes in acrodontan lizards, including EDA mutants showing the first vertebrate example of positional transformation in tooth identity, to assess the developmental origins and evolutionary patterning of tooth types and heterodonty. We reveal that pleurodont versus acrodont dentition can be determined by a simple mechanism, where modulation of tooth size through EDA signaling has major consequences on dental formula, thereby providing a new flexible tooth patterning model. Furthermore, such implication of morphoregulation in tooth evolution allows predicting the dental patterns characterizing extant and fossil lepidosaurian taxa at large scale. Together, the origins and diversification of tooth types, long a focus of multiple research fields, can now be approached through evo-devo approaches, highlighting the importance of underexplored dental features for illuminating major evolutionary patterns.
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Häärä O, Harjunmaa E, Lindfors PH, Huh SH, Fliniaux I, Åberg T, Jernvall J, Ornitz DM, Mikkola ML, Thesleff I. Ectodysplasin regulates activator-inhibitor balance in murine tooth development through Fgf20 signaling. Development 2012; 139:3189-99. [PMID: 22833125 DOI: 10.1242/dev.079558] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Uncovering the origin and nature of phenotypic variation within species is the first step in understanding variation between species. Mouse models with altered activities of crucial signal pathways have highlighted many important genes and signal networks regulating the morphogenesis of complex structures, such as teeth. The detailed analyses of these models have indicated that the balanced actions of a few pathways regulating cell behavior modulate the shape and number of teeth. Currently, however, most mouse models studied have had gross alteration of morphology, whereas analyses of more subtle modification of morphology are required to link developmental studies to evolutionary change. Here, we have analyzed a signaling network involving ectodysplasin (Eda) and fibroblast growth factor 20 (Fgf20) that subtly affects tooth morphogenesis. We found that Fgf20 is a major downstream effector of Eda and affects Eda-regulated characteristics of tooth morphogenesis, including the number, size and shape of teeth. Fgf20 function is compensated for by other Fgfs, in particular Fgf9 and Fgf4, and is part of an Fgf signaling loop between epithelium and mesenchyme. We showed that removal of Fgf20 in an Eda gain-of-function mouse model results in an Eda loss-of-function phenotype in terms of reduced tooth complexity and third molar appearance. However, the extra anterior molar, a structure lost during rodent evolution 50 million years ago, was stabilized in these mice.
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Affiliation(s)
- Otso Häärä
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, POB 56, 00014 Helsinki, Finland
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Catalán MA, Scott-Anne K, Klein MI, Koo H, Bowen WH, Melvin JE. Elevated incidence of dental caries in a mouse model of cystic fibrosis. PLoS One 2011; 6:e16549. [PMID: 21304986 PMCID: PMC3031584 DOI: 10.1371/journal.pone.0016549] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 12/23/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dental caries is the single most prevalent and costly infectious disease worldwide, affecting more than 90% of the population in the U.S. The development of dental cavities requires the colonization of the tooth surface by acid-producing bacteria, such as Streptococcus mutans. Saliva bicarbonate constitutes the main buffering system which neutralizes the pH fall generated by the plaque bacteria during sugar metabolism. We found that the saliva pH is severely decreased in a mouse model of cystic fibrosis disease (CF). Given the close relationship between pH and caries development, we hypothesized that caries incidence might be elevated in the mouse CF model. METHODOLOGY/PRINCIPAL FINDINGS We induced carious lesions in CF and wildtype mice by infecting their oral cavity with S. mutans, a well-studied cariogenic bacterium. After infection, the mice were fed a high-sucrose diet for 5 weeks (diet 2000). The mice were then euthanized and their jaws removed for caries scoring and bacterial counting. A dramatic increase in caries and severity of lesions scores were apparent in CF mice compared to their wildtype littermates. The elevated incidence of carious lesions correlated with a striking increase in the S. mutans viable population in dental plaque (20-fold increase in CF vs. wildtype mice; p value < 0.003; t test). We also found that the pilocarpine-stimulated saliva bicarbonate concentration was significantly reduced in CF mice (16 ± 2 mM vs. 31 ± 2 mM, CF and wildtype mice, respectively; p value < 0.01; t test). CONCLUSIONS/SIGNIFICANCE Considering that bicarbonate is the most important pH buffering system in saliva, and the adherence and survival of aciduric bacteria such as S. mutans are enhanced at low pH values, we speculate that the decrease in the bicarbonate content and pH buffering of the saliva is at least partially responsible for the increased severity of lesions observed in the CF mouse.
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Affiliation(s)
- Marcelo A. Catalán
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Kathleen Scott-Anne
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Marlise I. Klein
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Hyun Koo
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - William H. Bowen
- Center for Oral Biology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - James E. Melvin
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
- * E-mail:
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Abstract
It is known from paleontology studies that two premolars have been lost during mouse evolution. During mouse mandible development, two bud-like structures transiently form that may represent rudimentary precursors of the lost premolars. However, the interpretation of these structures and their significance for mouse molar development are highly controversial because of a lack of molecular data. Here, we searched for typical tooth signaling centers in these two bud-like structures, and followed their fate using molecular markers, 3D reconstructions, and lineage tracing in vitro. Transient signaling centers were indeed found to be located at the tips of both the anterior and posterior rudimentary buds. These centers expressed a similar set of molecular markers as the "primary enamel knot" (pEK), the signaling center of the first molar (M1). These two transient signaling centers were sequentially patterned before and anterior to the M1 pEK. We also determined the dynamics of the M1 pEK, which, slightly later during development, spread up to the field formerly occupied by the posterior transient signaling center. It can be concluded that two rudimentary tooth buds initiate the sequential development of the mouse molars and these have previously been mistaken for early stages of M1 development. Although neither rudiment progresses to form an adult tooth, the posterior one merges with the adjacent M1, which may explain the anterior enlargement of the M1 during mouse family evolution. This study highlights how rudiments of lost structures can stay integrated and participate in morphogenesis of functional organs and help in understanding their evolution, as Darwin suspected long ago.
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Sehic A, Peterkova R, Lesot H, Risnes S. Distribution and structure of the initial dental enamel formed in incisors of young wild-type and Tabby mice. Eur J Oral Sci 2010; 117:644-54. [PMID: 20121926 DOI: 10.1111/j.1600-0722.2009.00676.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mouse incisor enamel can be divided into four layers: an inner prism-free layer; an inner enamel with prism decussation; outer enamel with parallel prisms; and a superficial prism-free layer. We wanted to study how this complex structural organization is established in the very first enamel formed in wild-type mice and also in Tabby mice where enamel coverage varies considerably. Unworn incisors from young female wild-type and Tabby mice were ground, etched, and analyzed using scanning electron microscopy. In both wild-type and Tabby mice, establishment of the enamel structural characteristics in the initially formed enamel proceeded as follows, going from the incisal tip in an apical direction: (i) a zone with prism-free enamel, (ii) a zone with occasional prisms most often inclined incisally, and (iii) a zone where prism decussation was gradually established in the inner enamel. The distribution of enamel in Tabby mice exhibited considerable variability. The sequence of initial enamel formation in mouse incisors mimics development from a primitive (prism-free) structure to an evolved structure. It is suggested that genes controlling enamel distribution are not associated with genes controlling enamel structure. The control of ameloblast configuration, life span, organization in transverse rows, and movement is important for establishing the characteristic mature pattern of mouse incisor enamel.
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Affiliation(s)
- Amer Sehic
- Department of Oral Biology, University of Oslo, Oslo, Norway.
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Charles C, Pantalacci S, Peterkova R, Tafforeau P, Laudet V, Viriot L. Effect of eda loss of function on upper jugal tooth morphology. Anat Rec (Hoboken) 2009; 292:299-308. [PMID: 19051250 DOI: 10.1002/ar.20804] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The Tabby/eda mice, which bear a loss of function mutation for the eda (ectodysplasinA) gene, are known to display developmental anomalies in organs with an ectodermal origin. Although the lower jugal (cheek) teeth of Tabby/eda mice have been extensively studied, upper teeth have never been investigated in detail. However, this may help us to further understand the function of the eda gene in tooth development. In this work, the shape and size of both the crown and the radicular system were studied in the Tabby/eda mice upper jugal teeth. To deal with the high morphological variability, we defined several morphotypes based on cusp numbers and position. Statistical tests were then performed within and between the different morphotypes to test the correlation between tooth size and morphology. Our analysis reveals that, as in lower teeth, eda is necessary to segment the dental lamina into three teeth with the characteristic size and proportions of the mouse. Nevertheless, since strong effects are observed in heterozygous upper teeth while lower are only mildly affected, it seems that the upper jaw is more sensitive than the lower jaw to the loss of eda function. Modifications in cusp number and the abnormal crown size of the teeth are clearly linked, and our results indicate a role of eda in cusp patterning. Moreover, we found that the Tabby mutation induces variations in the dental root pattern, sometimes associated with hypercementosis, suggesting a newly uncovered role played by eda in root patterning and formation.
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Affiliation(s)
- Cyril Charles
- iPHEP, CNRS UMR 6046, Faculté SFA, Université de Poitiers, 40 avenue du recteur Pineau, Poitiers Cedex, France.
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Search for candidate chromosomes that specify mesiodistal tooth crown length of the mandibular first molar using MSM, C57BL/6J and their consomic mice. PEDIATRIC DENTAL JOURNAL 2009. [DOI: 10.1016/s0917-2394(09)70155-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Charles C, Pantalacci S, Peterkova R, Peterka M, Laudet V, Viriot L. Disruption of the palatal rugae pattern in Tabby (eda) mutant mice. Eur J Oral Sci 2007; 115:441-8. [DOI: 10.1111/j.1600-0722.2007.00482.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Casal ML, Lewis JR, Mauldin EA, Tardivel A, Ingold K, Favre M, Paradies F, Demotz S, Gaide O, Schneider P. Significant correction of disease after postnatal administration of recombinant ectodysplasin A in canine X-linked ectodermal dysplasia. Am J Hum Genet 2007; 81:1050-6. [PMID: 17924345 PMCID: PMC2265652 DOI: 10.1086/521988] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Accepted: 07/27/2007] [Indexed: 11/03/2022] Open
Abstract
Patients with defective ectodysplasin A (EDA) are affected by X-linked hypohidrotic ectodermal dysplasia (XLHED), a condition characterized by sparse hair, inability to sweat, decreased lacrimation, frequent pulmonary infections, and missing and malformed teeth. The canine model of XLHED was used to study the developmental impact of EDA on secondary dentition, since dogs have an entirely brachyodont, diphyodont dentition similar to that in humans, as opposed to mice, which have only permanent teeth (monophyodont dentition), some of which are very different (aradicular hypsodont) than brachyodont human teeth. Also, clinical signs in humans and dogs with XLHED are virtually identical, whereas several are missing in the murine equivalent. In our model, the genetically missing EDA was compensated for by postnatal intravenous administration of soluble recombinant EDA. Untreated XLHED dogs have an incomplete set of conically shaped teeth similar to those seen in human patients with XLHED. After treatment with EDA, significant normalization of adult teeth was achieved in four of five XLHED dogs. Moreover, treatment restored normal lacrimation and resistance to eye and airway infections and improved sweating ability. These results not only provide proof of concept for a potential treatment of this orphan disease but also demonstrate an essential role of EDA in the development of secondary dentition.
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Affiliation(s)
- Margret L Casal
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Tucker AS, Headon DJ, Courtney JM, Overbeek P, Sharpe PT. The activation level of the TNF family receptor, Edar, determines cusp number and tooth number during tooth development. Dev Biol 2004; 268:185-94. [PMID: 15031115 DOI: 10.1016/j.ydbio.2003.12.019] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2003] [Revised: 11/21/2003] [Accepted: 12/15/2003] [Indexed: 01/02/2023]
Abstract
Mutations in members of the ectodysplasin (TNF-related) signalling pathway, EDA, EDAR, and EDARADD in mice and humans produce an ectodermal dysplasia phenotype that includes missing teeth and smaller teeth with reduced cusps. Using the keratin 14 promoter to target expression of an activated form of Edar in transgenic mice, we show that expression of this transgene is able to rescue the tooth phenotype in Tabby (Eda) and Sleek (Edar) mutant mice. High levels of expression of the transgene in wild-type mice result in molar teeth with extra cusps, and in some cases supernumerary teeth, the opposite of the mutant phenotype. The level of activation of Edar thus determines cusp number and tooth number during tooth development.
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Affiliation(s)
- A S Tucker
- Craniofacial Development, Dental Institute, Guy's Hospital, King's College London, London SE1 9RT, UK
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Shimizu T, Oikawa H, Han J, Kurose E, Maeda T. Genetic analysis of crown size in the first molars using SMXA recombinant inbred mouse strains. J Dent Res 2004; 83:45-9. [PMID: 14691112 DOI: 10.1177/154405910408300109] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Tooth crown size may be determined by both genetic and environmental factors. The aim of this study was to identify quantitative trait loci (QTLs) affecting dental crown size and determine whether there is genetic independence between upper and lower teeth, using SMXA recombinant inbred strains of mice. Mesiodistal and buccolingual crown diameters (MD and BL, respectively) of the upper and lower first molars (M(1) and M(1), respectively) were measured. For each trait, mean values of substrains showed a continuous spectrum of distribution. Genome-wide scan detected QTLs exceeding suggestive threshold levels for MD of M(1) (chromosomes 7, 13, and 17), BL of M(1) (chromosomes 8 and 13), MD of M(1) (chromosomes 7 and 13), and BL of M(1) (chromosomes 3 and 15). These findings suggest that tooth crown size is controlled by multiple genes, and that there is some independence of genetic control between M(1) and M(1).
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Affiliation(s)
- T Shimizu
- Department of Pediatric Dentistry, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan.
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Gaide O, Schneider P. Permanent correction of an inherited ectodermal dysplasia with recombinant EDA. Nat Med 2003; 9:614-8. [PMID: 12692542 DOI: 10.1038/nm861] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2002] [Accepted: 03/14/2003] [Indexed: 01/26/2023]
Abstract
X-linked hypohidrotic ectodermal dysplasia (XLHED; OMIM 305100) is a genetic disorder characterized by absence or deficient function of hair, teeth and sweat glands. Affected children may experience life-threatening high fever resulting from reduced ability to sweat. Mice with the Tabby phenotype share many symptoms with human XLHED patients because both phenotypes are caused by mutations of the syntenic ectodysplasin A gene (Eda) on the X chromosome. Two main splice variants of Eda, encoding EDA1 and EDA2, engage the tumor necrosis factor (TNF) family receptors EDAR and XEDAR, respectively. The EDA1 protein, acting through EDAR, is essential for proper formation of skin appendages; the functions of EDA2 and XEDAR are not known. EDA1 must be proteolytically processed to a soluble form to be active. Here, we show that treatment of pregnant Tabby mice with a recombinant form of EDA1, engineered to cross the placental barrier, permanently rescues the Tabby phenotype in the offspring. Notably, sweat glands can also be induced by EDA1 after birth. This is the first example of a developmental genetic defect that can be permanently corrected by short-term treatment with a recombinant protein.
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Affiliation(s)
- Olivier Gaide
- Institute of Biochemistry, BIL Biomedical Research Center, University of Lausanne, CH-1066 Epalinges, Switzerland
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Peterková R, Kristenová P, Lesot H, Lisi S, Vonesch JL, Gendrault JL, Peterka M. Different morphotypes of the tabby (EDA) dentition in the mouse mandible result from a defect in the mesio-distal segmentation of dental epithelium. Orthod Craniofac Res 2002; 5:215-26. [PMID: 12416536 DOI: 10.1034/j.1600-0544.2002.02226.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVES Prenatal identification of the different dentition morphotypes, which exist in the lower molar region of tabby (Ta) adult mice, and investigation of their origin. The mouse Ta syndrome and its counterpart anhidrotic (hypohidrotic) ectodermal dysplasia (EDA) in human are characterized by absence or hypoplasia of sweat glands, hair and teeth. DESIGN Analysis of tooth morphogenesis using serial histological sections and 3D computer aided reconstructions of the dental epithelium in the cheek region of the mandible. SETTING AND SAMPLE POPULATION Institute of Experimental Medicine, Academy of Sciences, Prague. Heads of 75 Ta homozygous and hemizygous mice and 40 wild type (WT) control mice aged from embryonic day (ED) 14.0-20.5 (newborns), harvested during 1995-2001. OUTCOME MEASURE Prenatal identification of five distinct morphotypes of Ta dentition on the basis of differences in tooth number, size, shape, position and developmental stage and of the morphology of the enamel knot in the most mesial tooth primordium. RESULTS The mesio-distal length of the dental epithelium was similar in the lower cheek region in Ta and WT mice. In Ta embryos, there was altered the mesio-distal segmentation of the dental epithelium giving rise to the individual tooth primordia. Prenatally, two basic morphotypes I and II and their particular subtypes (Ia, Ib, Ic, and IIa, IIb, respectively) of the developing dentition were identified from day 15.5. The incidence of the distinct morphotypes in the present sample did not differ from postnatal data. The proportion of the morphotype I and II was dependent on mother genotype. CONCLUSION The different dentition morphotypes in Ta mice originate from a defect in the mesio-distal segmentation of the dental epithelium in mouse embryos. This defect presumably leads to variable positions of tooth boundaries that do not correspond to those of the WT molars. One tooth primordium of Ta mice might be derived from adjacent parts of two molar primordia in WT mice.
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Affiliation(s)
- R Peterková
- Institute of Experimental Medicine, Academy of Sciences CR, Prague, Czech Republic.
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Kristenová P, Peterka M, Lisi S, Gendrault JL, Lesot H, Peterková R. Different morphotypes of functional dentition in the lower molar region of tabby (EDA) mice. Orthod Craniofac Res 2002; 5:205-14. [PMID: 12416535 DOI: 10.1034/j.1600-0544.2002.02225.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVES To sort and classify the highly variable lower molar dentition in tabby (Ta) mice postnatally. The Ta syndome is homologous to the anhidrotic (hypohidrotic) ectodermal dysplasia (EDA) in human and includes severe developmental defects of teeth, hair and sweat glands. DESIGN Analysis of tooth shape and cusp pattern and measurement of the mesio-distal crown length. SETTING AND SAMPLE POPULATION Institute of Experimental Medicine, Academy of Sciences, Prague. Fixed heads of 107 tabby (Ta) homozygous and hemizygous mice and 90 wild type mice aged from post-natal day 11 to adulthood, collected during 1995-2001. OUTCOME MEASURE Identification of distinct morphotypes of Ta dentition. Reduced tooth length in Ta teeth and specific differences in tooth length between distinct morphotypes. RESULTS The variable dentitions in the lower molar region of Ta mice were classified in two basic morphotypes I and II. The morphotype I was further subdivided into particular morphotypes Ia, Ib and Ic. Proportion of the basic morphotypes I and II was different in the offspring of heterozygous (84% and 12%) compared with homozygous + hemizygous (45% and 52%) mothers. The proportions of particular morphotypes within a basic morphotype were similar in both offspring groups. CONCLUSION The identification of the distinct morphotypes made possible to classify the structural variability of the mandibular functional dentition in Ta mice.
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Affiliation(s)
- P Kristenová
- Institute of Experimental Medicine, Academy of Sciences CR, Prague, Czech Republic
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