A computational model of teeth and the developmental origins of morphological variation.
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 of microevolution. Here we report a computational model of mammalian tooth development that combines parameters of genetic and cellular interactions to produce a three-dimensional tooth from a simple tooth primordia. We systematically tinkered with each of the model parameters to generate phenotypic variation and used geometric morphometric analyses to identify, or developmentally ordinate, parameters best explaining population-level variation of real teeth. To model the full range of developmentally possible morphologies, we used a population sample of ringed seals (Phoca hispida ladogensis). Seal dentitions show a high degree of variation, typically linked to the lack of exact occlusion. Our model suggests that despite the complexity of development and teeth, there may be a simple basis for dental variation. Changes in single parameters regulating signalling during cusp development may explain shape variation among individuals, whereas a parameter regulating epithelial growth may explain serial, tooth-to-tooth variation along the jaw. Our study provides a step towards integrating the genotype, development and the phenotype.
Salazar-Ciudad
Isaac
I
Departament de Genètica i Microbiologia, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain. isaac.salazar@uab.cat
Jernvall
Jukka
J
D000818:Animals; D053263:Gene Regulatory Networks / Q000235:genetics; D005838:Genotype; D008954:Models, Biological; D010641:Phenotype; D046049:Phoca / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction; D014070:Tooth / Q000033:anatomy & histology* / Q000254:growth & development / Q000502:physiology*