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A structural biorhythm related to human sexual dimorphism
Patrick Mahoney1, Gina McFarlane1, Rosie Pitfield1
1School of Anthropology and Conservation, University of Kent, Canterbury CT2 7N, UK.
Journal of Structural Biology
|June 20, 2020
Summary
A near weekly biological rhythm, evidenced by Retzius periodicity (RP) in tooth enamel, shows sex differences. This rhythm influences human stature and enamel thickness, particularly in maxillary third molars.
Area of Science:
- Human biology
- Paleodontology
- Anthropology
Background:
- Biological rhythms influence life, including human skeletal growth.
- Retzius periodicity (RP) in tooth enamel reflects a near weekly biorhythm.
- Adult stature and enamel thickness exhibit sexual dimorphism.
Purpose of the Study:
- To analyze sex-related variation in RP and its relationship with enamel thickness.
- To investigate the influence of this biorhythm on sexually dimorphic traits.
- To determine if RP contributes to sex differences in enamel thickness.
Main Methods:
- Analysis of Retzius periodicity (RP) in maxillary and mandibular third molars (M3) from 94 adults in Northern Britain.
- Comparison of RP between male and female samples.
- Correlation analysis between RP and enamel thickness, considering tooth type (maxillary vs. mandibular M3).
Main Results:
- RP was significantly higher in females than males.
- RP in maxillary M3 correlated with sex differences in enamel thickness.
- No such relationship was found for mandibular M3.
- Maxillary M3 showed greater enamel thickness variation, facilitating detection of correlations.
Conclusions:
- The near weekly biorhythm, indicated by RP, is sexually dimorphic.
- RP is a potential factor contributing to sex differences in enamel thickness.
- Detecting correlations between RP and enamel thickness requires tooth types with sufficient variation, like maxillary M3.
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