135: Micronutrients and Modern Human Evolution

Rees J et al., The American Journal of Human Genetics - Rees et al. analyze signatures of positive selection in 276 genes linked to 13 dietary micronutrients across 40 global populations (HGDP). Using simulations and complementary selection scans, they report widespread local and oligogenic adaptation, with notable signals for zinc, iodine, and selenium. Key terms: micronutrients, positive selection, human evolution, local adaptation, zinc.

Study Highlights:
Using curated micronutrient-associated gene sets and whole-genome data from 913 individuals, the authors detect enriched signatures of positive selection across many populations. Power analyses with SLiM guided use of L_ST and Relate to identify both individual gene sweeps and oligogenic signals. SUMSTAT and CLUES2 timing analyses indicate some adaptations predate the Neolithic and align with migrations into novel soil environments. The results implicate micronutrient availability, driven by local geology and later cultural change, as a recurrent selective force in recent human evolution.

Conclusion:
Micronutrient-driven selection has likely shaped modern human genetic diversity more broadly than previously recognized; ongoing soil depletion and environmental change may increase risk of micronutrient-related disorders in populations lacking matching adaptations.

Music:
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Article title:
Global impact of micronutrients in modern human evolution

First author:
Rees J

Journal:
The American Journal of Human Genetics

DOI:
10.1016/j.ajhg.2025.08.005

Reference:
Rees J., Castellano S., Andrés A.M. Global impact of micronutrients in modern human evolution. The American Journal of Human Genetics. 2025;112:1–24. doi:10.1016/j.ajhg.2025.08.005

License:
© 2025 Published by Elsevier Inc. on behalf of American Society of Human Genetics.

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QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2025-09-12.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited transcript sections describing the study's design, methods (FST, Relate, CLUES2, SUMSTAT), core findings across iodine, zinc, selenium, and magnesium, timing analyses, and implications for precision nutrition and evolutionary health.
- transcript topics: Soil geology as driver of micronutrient variation; Zinc transporter adaptations and out-of-Africa migrations; Iodine deficiency and thyroid gene adaptations (THRA, THRB, TRIP4, IYD); Selenium-related oligogenic adaptation (SGCD, AKAP6, PRKG1, KCNMA1); Magnesium toxicity adaptation and Neanderthal introgression (MECOM, FXYD2); Timing of selection with CLUES2 (iron/calcium pre-Neolithic, 28–42 ka)

QC Summary:
- factual score: 10/10
- metadata score: 10/10
- supported core claims: 7
- claims flagged for review: 0
- metadata checks passed: 4
- metadata issues found: 0

Metadata Audited:
- article_doi
- article_title
- article_journal
- license

Factual Items Audited:
- 276 genes associated with 13 micronutrients analyzed; 269 MA genes after accessibility masking
- 40 populations; 913 HGDP individuals used in the analysis
- Methods included FST, Relate, CLUES2, SUMSTAT; haplotype networks (POPART) used for selected regions
- Key findings include iodine-associated adaptations in THRA/THRB/TRIP4/IYD and zinc transporter adaptations (SLC30A9, SLC39A11, SLC39A4) across non-African populations; selenium oli
- Transcript describes Neanderthal introgression contributing to magnesium-uptake adaptations via MECOM region
- Evolutionary timeline indicates adaptations long predate Neolithic farming for several nutrients

QC result: Pass.