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Multivariate structure of human populations: sedentary versus migrants
Human Heredity
|January 1, 1986
Summary
Migration significantly alters genetic correlations in polygenic traits, even when average values remain stable. Preselection of migrants may explain these changes in genetic structure.
Area of Science:
- Population genetics
- Quantitative genetics
- Human biology
Background:
- Gene frequency changes are influenced by emigration, reproductive size, and environmental selection pressures.
- Research on migration's impact on discrete traits is extensive, but its effect on quantitative, polygenic traits is less understood.
Observation:
- This study analyzed 20 anthropometric traits in Mexican families from sedentary (Mexico) and migrant (Texas) populations.
- Phenotypic, genetic, and environmental correlations were examined for changes in levels and structure between the two groups.
Findings:
- While distribution curves and average correlation values were consistent, the structure of phenotypic, genetic, and environmental correlation matrices changed significantly.
- Phenotypic correlations showed the highest stability (62.1% agreement), while genetic matrices exhibited the lowest correspondence (35.6% agreement).
- Environmental correlations displayed high variation with nonsignificant agreement (26.3%).
Implications:
- Migration can induce significant structural changes in genetic correlations, suggesting a nonrandom selection of migrating individuals.
- These findings highlight the importance of considering preselection effects in migration studies of polygenic traits.
- Understanding these shifts is crucial for predicting evolutionary trajectories and population adaptation.
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