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An Unexpectedly Complex Architecture for Skin Pigmentation in Africans
Alicia R Martin1, Meng Lin2, Julie M Granka3
1Department of Genetics, Stanford University, Stanford, CA 94305, USA; Analytic and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA 02141, USA; Stanley Center for Psychiatric Research, Broad Institute, Cambridge, MA 02141, USA.
Cell
|December 2, 2017
Summary
Human skin pigmentation is a complex polygenic trait, not a simple one. Genetic architecture varies by latitude, with known genes explaining little variance in KhoeSan populations.
Area of Science:
- Human genetics
- Evolutionary biology
- Anthropometry
Background:
- Human skin pigmentation was previously considered a simple trait with ~15 associated genes.
- Quantitative phenotypes suggest a more complex genetic architecture, potentially varying with latitude.
Purpose of the Study:
- To investigate the polygenicity of skin pigmentation in KhoeSan populations of southern Africa.
- To identify genetic loci associated with skin pigmentation in under-studied African populations.
Main Methods:
- Genome-wide association study (GWAS) complemented by targeted resequencing.
- Analysis of quantitative skin pigmentation phenotypes across diverse African populations.
Main Results:
- Skin pigmentation in KhoeSan is highly heritable but complex and polygenic.
- Known pigmentation loci explain only a small fraction of the observed variance.
- Identified canonical and non-canonical loci near SLC24A5, TYRP1, SMARCA2/VLDLR, and SNX13.
Conclusions:
- Human skin pigmentation is a complex, polygenic trait with architecture varying across populations and latitudes.
- Under-studied African populations provide crucial insights into the evolutionary pressures shaping skin pigmentation.
- Genetic studies in diverse populations are essential for a comprehensive understanding of human adaptation.
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