Detecting interregionally diversifying natural selection on modern human cranial form by using matched molecular and...

Area of Science:

• Human Evolution
• Anthropology
• Genetics

Background:

• Cranial morphology variation across human populations is a key area of study.
• Understanding evolutionary pressures requires comparing morphological and genetic data.

Purpose of the Study:

• To test the neutral hypothesis of human cranial evolution.
• To identify and explain deviations from neutral evolution in cranial morphology.
• To investigate the role of climate in human cranial diversification.

Main Methods:

• Comparison of morphological and neutral genetic variation in 10 human populations.
• Utilized partial Mantel's tests to account for population history and structure.
• Correlated cranial dimensions with climatic data, specifically temperature.

Main Results:

• Among-population cranial morphological differences generally correlate with neutral genetic differences.
• Most populations exhibit cranial morphology consistent with neutral evolutionary expectations.
• A Siberian population shows cranial morphology differentiation exceeding neutral expectations, particularly in skull breadth, vault size/shape, and nasal morphology.
• Correlation between cranial morphology and cold climate persisted after controlling for population structure.

Conclusions:

• Human cranial evolution is largely consistent with neutral processes, influenced by population history.
• The Siberian population's cranial morphology suggests adaptation to cold environments via natural selection.
• Regional climate, particularly temperature, appears to be a selective pressure driving specific cranial traits in some human populations.