Metamerism, morphogenesis, and the expression of carabelli and other dental traits in humans
Article first published online: 3 JAN 2013
Copyright © 2013 Wiley Periodicals, Inc.
American Journal of Physical Anthropology
Volume 150, Issue 3, pages 400–408, March 2013
How to Cite
Moormann, S., Guatelli-Steinberg, D. and Hunter, J. (2013), Metamerism, morphogenesis, and the expression of carabelli and other dental traits in humans. Am. J. Phys. Anthropol., 150: 400–408. doi: 10.1002/ajpa.22216
- Issue published online: 23 FEB 2013
- Article first published online: 3 JAN 2013
- Manuscript Accepted: 3 DEC 2012
- Manuscript Received: 10 APR 2012
- The Arts and Sciences Undergraduate Research Fellowship, The Ohio State University Newark Student Assistantship Grant
- patterning cascade model;
- dental development;
- dental evolution
The patterning cascade model of tooth morphogenesis has emerged as a useful tool in explaining how tooth shape develops and how tooth evolution may occur. Enamel knots, specialized areas of dental epithelium where cusps initiate, act as signaling centers that direct the growth of surrounding tissues. For a new cusp to form, an enamel knot must form beyond the inhibition fields of other enamel knots. The model predicts that the number and size of cusps depends on the spacing between enamel knots, reflected in the spacing between cusps. Recently, work by our group demonstrated that the model predicted Carabelli trait expression in human first molars. Here we test whether differences in Carabelli trait expression along the molar row can also be predicted by the model. Crown areas and intercusp distances were measured from dental casts of 316 individuals with a digital microscope. Although absolute cusp spacing is similar in first and second molars, the smaller size and more triangular shape of second molars results in larger cusp spacing relative to size and, likely, less opportunity for the Carabelli trait to form. The presence and size of the hypocone (HY) and a range of small accessory cusps in a larger sample of 340 individuals were also found to covary with the Carabelli trait in a complex way. The results of this study lend further support to the view that the dentition develops, varies, and evolves as a single functional complex. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.