Evolutionary origin of teeth

Martin Rucklin, Philip Donoghue

Research output: Contribution to journalReview article (Academic Journal)peer-review

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Teeth and jaws have been widely perceived as key innovations underpinning the adaptive radiation and the evolutionary success of jawed vertebrates. However, the origin, evolution, and developmental evolution of teeth are all the subject of controversy. There are three competing hypotheses that are more or less well supported by the available data: (i) the ‘outside-in’ hypothesis which contends that odontogenic competence spread from the external dermis to the oro-pharynx – the traditional hypothesis based on the observation that teeth and scales exhibit common patterns of development that extend to the molecular genetic level, combined with evidence that scales appear before teeth within phylogeny; (ii) the ‘inside-out’ hypothesis that teeth and scales evolved independently, based on the observation that some jawless scale-covered vertebrates also possess oro-pharyngeal scales, and (iii) the ‘inside-outside’ hypothesis which is effectively agnostic on the question. The available evidence supports an origin of teeth through extension of odontogenic competence from the external dermis to the oro-pharynx.
Original languageEnglish
Number of pages7
JournalEncyclopaedia of Life Sciences
Early online date29 Jul 2019
Publication statusE-pub ahead of print - 29 Jul 2019


  • teeth
  • development
  • evolution
  • vertebrates
  • key innovations
  • whole genome duplication
  • Neural Crest
  • homology
  • phylogenetic congruence


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