Editor's Summary
9 October 2008
The evolution of teeth: word of mouth
The classical view of the evolution of vertebrate teeth is the 'outside-in' model, in which the oral cavity and oral teeth arise from the ectoderm by invagination. A study of transgenic axolotls (a type of salamander) now suggests that the picture is more complicated than that. Fate mapping of cells in the embryo reveals that oral teeth are derived from both ectoderm and endoderm: some even have a mixed ecto/endodermal origin. This implies a dominant role for neural crest mesenchyme over epithelia in tooth formation. The evolutionary implication is that the tooth-forming capacity of neural crest cells was the essential factor for teeth evolution, regardless of the 'outside-in' and 'inside-out' manoeuvres of the epithelium.
News and Views: Developmental biology: Teeth in double trouble
Almost all vertebrates have teeth of some sort. But where, in developmental terms, do teeth come from? Results drawn from experimental embryology provide an illuminating perspective on this contentious question.
Georgy Koentges
doi:10.1038/455747a
Letter: Dual epithelial origin of vertebrate oral teeth
Vladimír Soukup, Hans-Henning Epperlein, Ivan Horácek & Robert Cerny
doi:10.1038/nature07304
First paragraph | Full Text | PDF (1,105K) | Supplementary information
