MitochondriaHumans

Darker skin pigmentation links to fewer mitochondrial DNA mutations from sun exposure

Melanin protects against mitochondrial genome damage and clonal expansion in chronically sun-exposed human skin.

Pigment Cell & Melanoma Research

In an observational study of six older men, researchers analyzed how skin pigmentation influences mitochondrial DNA (mtDNA) stability under chronic sun exposure. The team performed targeted mitochondrial sequencing on paired skin biopsies from the photoexposed forearms and photoprotected buttocks of three Black African and three White Northern European participants. They identified 21 high-confidence somatic mtDNA variants across the samples. Photoexposed light skin possessed six-fold more variants than dark skin and was enriched for ultraviolet radiation signatures, such as C>T transitions and CC>TT substitutions. These variants in light skin altered multiple oxidative phosphorylation genes and frequently reached moderate-to-high heteroplasmy. Conversely, dark skin displayed a narrower variant profile dominated by a recurrent T414G substitution and lower overall heteroplasmy.

Why it matters

Mitochondrial genomic instability and respiratory chain impairment are hallmarks of tissue aging. Showing that melanin shields mitochondrial DNA helps explain why darker skin shows greater structural resistance to ultraviolet-induced photoaging.

Caveats

The findings are based on a very small sample size of six male donors and rely on an observational study design. Larger, more diverse cohorts are needed to confirm how broadly these findings apply across sexes and skin types.

The paper

Skin Pigmentation Associates With Reduced mtDNA Variant Burden in Photoexposed Skin

Mambwe B, Langton AK

Pigment Cell & Melanoma Research · 3 Oct 2026

doi.org/10.1111/pcmr.70123 PubMed

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