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Mammalian tooth forms are produced during development by folding of the enamel epithelium but the molecular mechanisms involved in the formation and patterning of tooth cusps are not understood. We now report that several key signaling molecules found in well-known vertebrate signaling tissues such as the node, the notochord, the apical ectodermal ridge,(More)
Mammalian dentition consists of teeth that develop as discrete organs. From anterior to posterior, the dentition is divided into regions of incisor, canine, premolar and molar tooth types. Particularly teeth in the molar region are very diverse in shape. The development of individual teeth involves epithelial-mesenchymal interactions that are mediated by(More)
A classic example of adaptive radiation is the diversification of Cenozoic ungulates into herbivore adaptive zones. Their taxonomic diversification has been associated with changes in molar tooth morphology. Analysis of molar crown types of the Artiodactyla, Perissodactyla, and archaic ungulates ("Condylarthra") shows that the diversity of genera and crown(More)
One motivation in the study of development is the discovery of mechanisms that may guide evolutionary change. Here we report how development governs relative size and number of cheek teeth, or molars, in the mouse. We constructed an inhibitory cascade model by experimentally uncovering the activator-inhibitor logic of sequential tooth development. The(More)
Generation of morphological diversity remains a challenge for evolutionary biologists because it is unclear how an ultimately finite number of genes involved in initial pattern formation integrates with morphogenesis. Ideally, models used to search for the simplest developmental principles on how genes produce form should account for both developmental(More)
The study of mammalian evolution depends greatly on understanding the evolution of teeth and the relationship of tooth shape to diet. Links between gross tooth shape, function and diet have been proposed since antiquity, stretching from Aristotle to Cuvier, Owen and Osborn. So far, however, the possibilities for exhaustive, quantitative comparisons between(More)
Primate molar shapes reflect developmental and ecological processes. Development may constrain as well as facilitate evolution of new tooth shapes, affecting how reliable dental characters are in phylogenetic studies. Much of the genetic machinery of development uses the same genes among different organs, including teeth, limbs, and feathers. Furthermore,(More)
Mammalian tooth crowns have precise functional requirements but cannot be substantially remodeled after eruption. In developing teeth, epithelial signaling centers, the enamel knots, form at future cusp positions and are the first signs of cusp patterns that distinguish species. We report that ectodin, a secreted bone morphogenetic protein (BMP) inhibitor,(More)
We present a classification of developmental mechanisms that have been shown experimentally to generate pattern and form in metazoan organisms. We propose that all such mechanisms can be organized into three basic categories and that two of these may act as composite mechanisms in two different ways. The simple categories are cell autonomous mechanisms in(More)
The relationship between the genotype and the phenotype, or the genotype-phenotype map, is generally approached with the tools of multivariate quantitative genetics and morphometrics. Whereas studies of development and mathematical models of development may offer new insights into the genotype-phenotype map, the challenge is to make them useful at the level(More)