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The genetic correlation between height and IQ: shared genes or assortative mating?
Matthew C Keller1, Christine E Garver-Apgar, Margaret J Wright
1Department of Psychology and Neuroscience, University of Colorado Boulder, Boulder, Colorado, United States of America. matthew.c.keller@gmail.com
Plos Genetics
|April 18, 2013
Summary
The genetic correlation between human height and IQ is substantial, driven by both shared genes (pleiotropy) and assortative mating. These factors significantly contribute to the observed link between these sexually selected traits.
Area of Science:
- Evolutionary Psychology
- Behavioral Genetics
- Human Mating
Background:
- Sexually selected traits often exhibit positive correlations with genetic underpinnings.
- Genetic correlations between traits can arise from pleiotropy (genes affecting multiple traits) or assortative mating (non-random mating patterns).
Purpose of the Study:
- To investigate the genetic and environmental basis of the correlation between human height and IQ.
- To account for the influence of assortative mating on trait correlations using a comprehensive family study design.
Main Methods:
- Utilized a large-scale twin and family study (N=7,905) including parents and siblings.
- Modeled covariation to estimate additive genetic, non-additive genetic, and shared environmental influences.
- Incorporated statistical methods to control for assortative mating effects.
Main Results:
- Both height and IQ demonstrated high heritability, with greater non-additive genetic influences observed in males.
- After controlling for assortative mating, the height-IQ correlation was found to be predominantly genetic.
- Pleiotropy and assortative mating were identified as significant and roughly equal contributors to the genetic correlation.
Conclusions:
- The positive correlation between height and IQ in humans is largely explained by shared genetic factors.
- Both pleiotropy and assortative mating play crucial, balanced roles in establishing this genetic correlation between sexually selected traits.
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