I remember in high school learning about Punnet squares; people with dark hair had the dominant hair color gene, and the redhead gene was recessive. It turns out it isn’t nearly as simple as having a red hair gene or a brown hair gene. (Nor is there a blue eye gene or a short gene…) Instead, certain variants in the MC1R gene control the red pigmentation in the hair.
The genetic variant that causes red shades of hair impacts other aspects of our health as well. Carrying the variant can cause an increased risk of melanoma and may also possibly impact the way you respond to certain analgesics.
Hair Color Genes: What Makes it Red?
There are two types of pigments for hair color: eumelanin and pheomelanin.
- Eumelanin comes in either black or brown, with varying amounts responsible for ranges of hair color from blond (low eumelanin) to black (high eumelanin).
- Pheomelanin contributes to red and orange coloring.
- Most people have both eumelanin and pheomelanin, and the varying amounts of each protein contribute to the wide range of hair colors that people naturally have.
The MC1R (melanocortin-1 receptor) gene controls how much melanin vs pheomelanin is produced in the skin and hair. Genetic variants of MC1R produce different amounts of pheomelanin, with increased pheomelanin causing red hair and skin to be more photosensitive.
Melanoma Risk for Red Hair:
The variant forms of MC1R are also thought to not activate DNA repair, as well as the more common MC1R form. This leads to higher rates of mutations in the DNA of skin cells, possibly leading to skin cancer.[ref]
The link to melanoma is well established for the common MC1R variants that cause red hair, but what people may not realize is that carrying one copy of the variant also doubles the risk of melanoma.[ref]
Freckles and moles are genetic:
The MC1R gene is also linked to freckles and more moles on the skin.[ref] Additionally, one MC1R variant (rs1805008) has also been tied to an increased risk of Parkinson’s disease.[ref]
Beyond red hair in people: MC1R function
MC1R isn’t just a human-specific gene; it causes pigmentation variation in animals from chickens to goats to fish. It is also thought to be involved in the browning reaction of cut apples being exposed to air.
Beyond the ‘red hair’ gene, predicting hair color from genetic data can be tricky. Here is a great article on 124 genes that influence hair color.
Additionally, a lot of men who carry one copy of the MC1R variant may notice that their beard hair is reddish, especially in the sunlight. The Irish call this a ‘gingerbeard’.
MC1R & Redhair Genotype Report:
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Lifehacks for MCR1:
Common sense dictates watching your sun exposure and avoiding a sunburn if you carry one of the risk variants listed above for melanoma.
While you need a certain amount of sun for vitamin D production, knowing when to cover up or put on sunscreen is important. In other words – avoid staying in the sun to the point that your skin starts to turn pink.
Research on supplements to keep you from getting sunburned:
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References:
Castejón-Griñán, María, et al. “CAMP-Independent Non-Pigmentary Actions of Variant Melanocortin 1 Receptor: AKT-Mediated Activation of Protective Responses to Oxidative DNA Damage.” Oncogene, vol. 37, no. 27, July 2018, pp. 3631–46. PubMed, https://doi.org/10.1038/s41388-018-0216-1.
Chen, Xiqun, et al. “Red Hair, MC1R Variants, and Risk for Parkinson’s Disease – a Meta‐analysis.” Annals of Clinical and Translational Neurology, vol. 4, no. 3, Feb. 2017, pp. 212–16. PubMed Central, https://doi.org/10.1002/acn3.381.
Cust, Anne E., et al. “MC1R Genotypes and Risk of Melanoma before Age 40 Years: A Population-Based Case-Control-Family Study.” International Journal of Cancer, vol. 131, no. 3, Aug. 2012, pp. E269-281. PubMed, https://doi.org/10.1002/ijc.27357.
Hepp, Diego, et al. “Prediction of the Damage-Associated Non-Synonymous Single Nucleotide Polymorphisms in the Human MC1R Gene.” PloS One, vol. 10, no. 3, 2015, p. e0121812. PubMed, https://doi.org/10.1371/journal.pone.0121812.
Ito, Naoki, et al. “The Protective Role of Astaxanthin for UV-Induced Skin Deterioration in Healthy People-A Randomized, Double-Blind, Placebo-Controlled Trial.” Nutrients, vol. 10, no. 7, June 2018, p. 817. PubMed, https://doi.org/10.3390/nu10070817.
Kohli, Indermeet, et al. “The Impact of Oral Polypodium Leucotomos Extract on Ultraviolet B Response: A Human Clinical Study.” Journal of the American Academy of Dermatology, vol. 77, no. 1, July 2017, pp. 33-41.e1. PubMed Central, https://doi.org/10.1016/j.jaad.2017.01.044.
Liem, Edwin B., et al. “Anesthetic Requirement Is Increased in Redheads.” Anesthesiology, vol. 101, no. 2, Aug. 2004, pp. 279–83. PubMed Central, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1362956/.
Mogil, Jeffrey S., et al. “The Melanocortin-1 Receptor Gene Mediates Female-Specific Mechanisms of Analgesia in Mice and Humans.” Proceedings of the National Academy of Sciences of the United States of America, vol. 100, no. 8, Apr. 2003, pp. 4867–72. PubMed, https://doi.org/10.1073/pnas.0730053100.
Siewierska-Górska, A., et al. “Association of Five SNPs with Human Hair Colour in the Polish Population.” Homo: Internationale Zeitschrift Fur Die Vergleichende Forschung Am Menschen, vol. 68, no. 2, Mar. 2017, pp. 134–44. PubMed, https://doi.org/10.1016/j.jchb.2017.02.002.
Sunscreens, EWG’s Guide to. EWG’s Guide to Safer Sunscreens. https://www.ewg.org/sunscreen/report/the-trouble-with-sunscreen-chemicals/. Accessed 14 Feb. 2023.
—. Sunscreen Guide – Rated by Scientists | EWG. https://www.ewg.org/sunscreen/. Accessed 14 Feb. 2023.
Tagliabue, E., et al. “MC1R Gene Variants and Non-Melanoma Skin Cancer: A Pooled-Analysis from the M-SKIP Project.” British Journal of Cancer, vol. 113, no. 2, July 2015, pp. 354–63. PubMed, https://doi.org/10.1038/bjc.2015.231.
Tell-Marti, Gemma, Joan Anton Puig-Butille, Miriam Potrony, Estel Plana, et al. “A Common Variant in the MC1R Gene (p.V92M) Is Associated with Alzheimer’s Disease Risk.” Journal of Alzheimer’s Disease: JAD, vol. 56, no. 3, 2017, pp. 1065–74. PubMed, https://doi.org/10.3233/JAD-161113.
Tell-Marti, Gemma, Joan Anton Puig-Butille, Miriam Potrony, Celia Badenas, et al. “The MC1R Melanoma Risk Variant p.R160W Is Associated with Parkinson Disease.” Annals of Neurology, vol. 77, no. 5, May 2015, pp. 889–94. PubMed, https://doi.org/10.1002/ana.24373.
Vallone, María Gabriela, et al. “Melanocortin 1 Receptor (MC1R) Polymorphisms’ Influence on Size and Dermoscopic Features of Nevi.” Pigment Cell & Melanoma Research, vol. 31, no. 1, Jan. 2018, pp. 39–50. PubMed, https://doi.org/10.1111/pcmr.12646.
“Why Are All Irish Men’s Beards Red?” IrishCentral.Com, 4 Nov. 2022, http://www.irishcentral.com/news/education/Finally-science-explains-why-all-Irish-mens-beards-are-red.html.
