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Updated: Dec 6, 2025
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Micro-dissection of Enamel Organ from Mandibular Incisor of Rats Exposed to Environmental Toxicants
Published on: March 29, 2018
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Neutral evolution of human enamel-dentine junction morphology
Tesla A Monson1, Diego Fecker2, Marc Scherrer2
1Department of Anthropology, Western Washington University, Bellingham, WA 98225; tesla.monson@wwu.edu.
Summary
The enamel-dentine junction (EDJ) morphology of human molars evolves neutrally, reflecting population history. However, its global distribution does not align with the Out of Africa dispersal model, offering new insights into human evolution.
Area of Science:
- Paleoanthropology
- Evolutionary Biology
- Bioarchaeology
Background:
- Tooth enamel outer surface traits offer insights into human evolution and population structure.
- Wear and taphonomy limit the study of outer enamel traits in fossil and archaeological specimens.
- Enamel-dentine junction (EDJ) morphology preserves anatomy in worn specimens and provides information on tooth development and vertebrate evolution.
Purpose of the Study:
- To investigate molar EDJ morphology variation across diverse human populations.
- To compare EDJ morphology variation with neutral evolution expectations and Out of Africa dispersal models.
- To enhance understanding of human dental variation and its application to population history.
Main Methods:
- Micro-CT (μ-CT) biomedical imaging of molar EDJ morphology in 161 late Holocene modern humans.
- Geometric morphometric analyses to assess EDJ shape variation.
- Comparison of phenetic variation with neutral genetic variation and dispersal models.
Main Results:
- Significant correlations observed between EDJ phenetic variation and neutral genetic variation, indicating neutral evolution.
- EDJ morphology reflects human population history.
- Global EDJ morphology distribution does not conform to the Out of Africa dispersal model predictions.
Conclusions:
- Human EDJ morphology evolves neutrally and can be used to infer population history.
- The study expands knowledge of human dental variation and dental development.
- Findings have implications for investigating human population history and genetic structure.
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