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Common evolutionary patterns in the human nasal region across a worldwide sample.
Cathy Ngọc Hân Tran1,2, Lauren Schroeder3,4
1Forensic Science Program, Department of Anthropology, University of Toronto Mississauga, Mississauga, Canada.
American Journal of Physical Anthropology
|July 31, 2021
Summary
Human nasal shape variation is driven by adaptation, not just genetic drift. This adaptation is present across all populations, not solely those in cold climates.
Area of Science:
- Human evolutionary biology
- Anthropometry
- Quantitative genetics
Background:
- Human nasal morphology variation is often linked to climatic adaptations like thermoregulation.
- Previous research suggested cold climates drive nasal region diversity.
Purpose of the Study:
- To test if human nasal variation is due to neutral processes (genetic drift) or adaptive evolution.
- To investigate the role of climate in shaping nasal morphology.
Main Methods:
- Utilized a quantitative genetics approach (Lande model) on craniometric data from 28 human populations (n=2504).
- Analyzed 20 external skeletal measurements of the nasal region.
- Applied evolutionary quantitative genetics statistical tests to assess divergence patterns under a genetic drift null hypothesis.
Main Results:
- Genetic drift was rejected as the sole explanation for nasal region variation across all analyses.
- Non-random evolutionary forces significantly contribute to human nasal diversity.
- This pattern held true when analyzing all populations, cold-climate populations only, and with cold-climate populations excluded.
Conclusions:
- Human nasal region adaptation is not exclusive to cold-climate populations.
- The propensity for nasal adaptation is a shared trait across diverse human populations.
- Evolutionary forces beyond neutral drift shape human nasal morphology globally.
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