The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)


Papa was a gnathostome (and Mama was dentate): modeling primate jaw and tooth evo-devo using a “toothless” mouse mutant

JULIA C. BOUGHNER1, ULLAS KAPOOR2 and MUHAMMAD T. RAJ1.

1Anatomy and Cell Biology, University of Saskatchewan, 2College of Dentistry, University of Saskatchewan

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The evolutionary developmental (evo-devo) biology of primate jaws and teeth is vital to studies of human evolution for several reasons. Dentitions and jaw bones are often the best if not only fossil primate remains found. Jaw and tooth morphology is central to identifying many fossil taxa. Dental development data are the chief means of inferring fossil primate life histories. Thus it benefits paleoanthropologists to consider the genetic processes underlying observed variation in primate tooth and jaw morphology and development.

The challenge is doing experimental genetic work when it is not possible to study the oral-facial developmental biology of fossil or living primates for ethical or logistical reasons. A viable solution is to use a non-primate model. The laboratory mouse is classically used to study human oral-facial development. Taken further, mouse is a valuable model with which to address primate jaw and tooth evo-devo.

The molecular mechanisms that coordinate viable developmental and evolutionary changes in primate teeth and jaws are unknown. Using microarray gene expression studies we test the hypothesis that tooth and jaw developmental timing is regulated independently of each other. We use a “toothless” p63-/- mouse mutant with normal mandible development but failed tooth development. Importantly, this “toothless” mouse enables genetic studies of jaw development in relative isolation of odontogenesis. In “toothless” embryos aged days 10-13 we identified a tooth-exclusive suite of genes including collagen, keratin and claudin families. This supports the hypothesis that odontogenesis is regulated by a gene expression network independent of jaw development and, perhaps, evolution.

This study was funded by the Natural Sciences and Engineering Research Council of Canada, the University of Saskatchewan Colleges of Medicine and Dentistry, the University of Calgary Research Grants Committee, with support from Génome Québec Innovation Centre.

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