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Natural selection, genetic drift, and trait correlation shaped hominin midfoot evolution
Klara Komza1,2, Bence Viola3, Lauren Schroeder4,5
1Department of Anthropology, Dartmouth College, Hanover, NH, USA. klara.komza@dartmouth.edu.
Nature Communications
|June 10, 2026
Summary
Hominin midfoot evolution involved genetic drift and selection, not just adaptation for upright walking. These processes, including correlations between foot elements, shaped diversity in our ancestors' feet.
Area of Science:
- Paleoanthropology
- Evolutionary Biology
- Quantitative Genetics
Background:
- The hominin foot shows significant changes related to upright walking.
- The midfoot is crucial for terrestrial bipedal locomotion and is a focus of natural selection.
- Previous research indicated early bipedalism selection targeted lateral foot elements, with later australopiths showing less diversity and selection on these compared to medial elements.
Purpose of the Study:
- To investigate evolutionary processes (directional vs. stabilizing selection) influencing hominin midfoot diversification.
- To test these processes against a null hypothesis of genetic drift.
- To understand the selective pressures on hominin foot evolution.
Main Methods:
- Application of quantitative genetics methods.
- Analysis of morphological diversity in the hominin midfoot.
- Testing evolutionary models against genetic drift.
Main Results:
- Early hominins like Ardipithecus ramidus may have had their lateral midfoot as a primary target of selection for bipedalism.
- Later hominin evolution did not consistently show lateral elements being less influenced by directional selection.
- Midfoot diversification resulted from a complex interplay of genetic drift, directional selection, and indirect selection due to element correlations.
Conclusions:
- Evolution of bipedalism in hominins is shaped by genetic drift and correlations among skeletal elements.
- These underestimated factors play a significant role in hominin midfoot evolution.
- Future narratives of bipedalism evolution should incorporate genetic drift and inter-element correlations.
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