Computerized reconstruction of prenatal growth trajectories in the dentition: Implications for the taxonomic status of neandertals

Patricia Smith*, Gal Avishai, Ralph Müller, Yankel Gabet

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

2 Scopus citations

Abstract

The hierarchical pattern of tooth formation means that successive phases of development can be identified in fully formed teeth offering a unique insight into ontogenetic processes. The spatial geometry of the cusps expressed in the topography of the dentin-enamel junction (DEJ) records the partitioning of cell proliferation and differentiation as well as the timing of these events. The final stage of development is expressed in the topography of the fully formed crown (OES). Here, the overlying shell of enamel increases crown volume, while modifying cusp relations seen at the DEJ reflecting local variations in enamel thickness. Using serial scans taken with a micro-CT at 16 μm we have developed a three-dimensional model that enables us to identify, and more importantly quantify, all these developmental features. We have applied this model to reconstruct growth trajectories and their impact on tooth size and cusp relationships in teeth of varying size and tooth classes. The results are used to interpret the extent of developmental variation expressed in Neandertal molars. They indicate that the characteristic features of Neandertal teeth, expressed in intercusp distances and proportions, thin enamel and taurodont roots represent a different partitioning of cell division and differentiation from that observed in Homo sapiens sapiens. Our findings indicate the existence of differences between Neandertals and other hominins in genes controlling the switch-on/switch-off mechanism that regulates the timing, rate and spatial organization of cell proliferation and differentiation of epithelial derived tissues. The thin Neandertal enamel results in teeth that wear down fast, resulting in loss of dental function. We propose that the changes observed in Neandertal teeth, may be secondary to those occurring in other organs developing from epithelial-mesenchymal interaction, with greater adaptive significance.

Original languageEnglish
Title of host publicationVertebrate Paleobiology and Paleoanthropology
PublisherSpringer
Pages165-173
Number of pages9
Edition9789400704916
DOIs
StatePublished - 2011
Externally publishedYes

Publication series

NameVertebrate Paleobiology and Paleoanthropology
Number9789400704916
ISSN (Print)1877-9077

Bibliographical note

Publisher Copyright:
© Springer Science+Business Media B.V. 2011.

Keywords

  • micro-CT
  • Neandertal - Homo sapiens sapiens
  • Ontogenesis
  • Tooth formation

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