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Genetic and environmental contributions to variation in human tooth size
1South Australian Centre for Rural and Remote Health, University of South Australia, Nicolson Ave., Whyalla Norrie, 5608, Australia.
Heredity
|October 12, 2001
Summary
Genetic factors significantly influence human dental crown dimensions, with additive genetic variation accounting for most phenotypic variation. Shared environmental factors impact maxillary first molars, suggesting early developmental influences on tooth size.
Area of Science:
- Human genetics
- Anthropology
- Developmental biology
Background:
- Human dental crown morphology is complex, with origins not fully understood.
- Previous research lacked comprehensive genetic and environmental analyses of tooth dimensions.
Purpose of the Study:
- To quantitatively assess the genetic and environmental contributions to human dental crown dimensions (mesiodistal and buccolingual).
- To investigate the ontogeny of dental crown morphology using biometrical modeling.
Main Methods:
- Analysis of dental crown diameters (mesiodistal and buccolingual) from nearly 600 monozygotic and dizygotic twins.
- Application of univariate biometrical models to data from 28 permanent teeth (excluding third molars).
Main Results:
- Additive genetic variation significantly contributed to all 56 measured variables, ranging from 56% to 92% of phenotypic variation (most >80%).
- Individual environmental effects ranged from 8% to 29%.
- Shared environmental factors (uterine/early childhood) significantly affected maxillary first molar dimensions (22-27%), and non-additive genetic variation was noted in canine and first premolar mesiodistal diameters.
Conclusions:
- Dental crown dimensions are predominantly heritable, with strong additive genetic influences.
- Shared early environmental factors play a role in specific tooth dimensions, particularly first molars.
- Non-additive genetic variation suggests evolutionary selection pressures on certain tooth types.
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