The possibility that redheaded people are more intelligent due to variations in the MC1R (Melanocortin 1 Receptor) gene is an interesting hypothesis, but one that should be analyzed with caution. The MC1R gene, known to influence skin and hair pigmentation, particularly associated with red hair and fair skin, also plays roles in biological processes that can indirectly affect human cognition.
It is important to clarify the use of terms related to the MC1R gene and its variants. All humans have the MC1R gene, which is responsible for the production of melanocortin 1, a protein involved in regulating skin and hair pigmentation. What varies between individuals are the alleles of this gene, which can result in different phenotypes, such as red hair color.
For a person to have red hair, they must have two recessive copies (alleles) of the MC1R variant. However, individuals may carry a single copy (heterozygous) of the variant without expressing the redheaded phenotype, especially if the other copy of the gene (allele) is not the recessive variant associated with redheaded hair. This article explores whether these variants could have indirect effects on cognition, even in the absence of the redhead phenotype. This article explores whether these variants could have indirect effects on cognition, even in the absence of the redhead phenotype.
Biological Basis and Hypothesis
Regulation of Oxidative Stress and Inflammation
The MC1R gene plays a significant role in responding to oxidative stress and regulating inflammation. Studies show that MC1R contributes to the production of antioxidants that protect cells against oxidative damage and reduce chronic inflammation (HEALY, 2004; MUN et al., 2023). MC1R variants associated with red hair may influence these capabilities:
- Antioxidant Production : MC1R variants that result in red hair are associated with greater production of pheomelanin, which is less effective at neutralizing free radicals compared to eumelanin. However, some studies suggest that these variants may increase antioxidant production in other pathways to compensate, helping to protect cells against oxidative damage (GARCIA-BORRON et al., 2005).
- Reducing Chronic Inflammation : MC1R variants linked to red hair may also influence the regulation of inflammation. Chronic inflammation is a known risk factor for several neurodegenerative diseases, such as Alzheimer’s and Parkinson’s. Therefore, the ability of these variants to improve the regulation of inflammation may hypothetically benefit brain health and, by extension, cognitive function (DUFFY et al., 2004).
DNA Repair and Genomic Stability
MC1R is involved in DNA repair capacity. Functional variants of this gene increase the repair efficiency of DNA damage induced by UV radiation and reduce the generation of reactive oxygen species, protecting the integrity of cellular DNA (LANDI et al., 2006). Maintaining genomic stability is crucial to prevent mutations that can lead to neuronal dysfunction. Thus, MC1R variants that improve these capabilities may be associated with better cognitive health regardless of red hair phenotype.
Inflammation and Neurogenesis
Chronic inflammation can inhibit neurogenesis, the process of forming new neurons in the brain. MC1R’s ability to regulate inflammation may promote neurogenesis, essential for brain plasticity and cognitive functions such as learning and memory (DUFFY et al., 2004). This suggests that individuals with MC1R variants that promote a controlled inflammatory response could have cognitive advantages, even if they do not present the redhead phenotype.
Mental Health and Psychological Wellbeing
Chronic inflammation and oxidative stress are risk factors for mental disorders such as depression and anxiety. MC1R variants that positively modulate these responses could indirectly promote better psychological well-being, which is essential for healthy cognitive function (DUFFY et al., 2004).
Genomic Considerations
Although MC1R-influenced pigmentation is a clear phenotypic characteristic, its biological implications go beyond aesthetics. The capacity for DNA repair and the regulation of oxidative stress, both influenced by MC1R, are critical processes in maintaining cellular health (GARCIA-BORRON et al., 2005). The influence of these processes on cognitive function is a promising area of study in neuroscience and genomics.
Evidence and Studies
While there are these biological mechanisms that suggest a possible indirect advantage of red hair-associated MC1R variants for brain health, there is currently no direct scientific evidence proving that these variants result in superior cognitive development. Intelligence is influenced by a complex combination of genetic and environmental factors, and the contribution of a single gene or variant is usually small in the overall picture.
Limitations and Conclusion
It is crucial to emphasize that intelligence is a highly complex and multifactorial trait. The interaction of countless genes, along with environmental and educational factors, determines human cognition. To date, there is no direct and conclusive evidence linking the MC1R gene to greater intelligence in redheads.
Therefore, although the hypothesis that MC1R variants may confer cognitive advantages is interesting and plausible based on the biological processes it regulates, it remains speculative. Future studies would be needed to explore this possibility more definitively.
References
DUFFY, DL, BOX, NF, CHEN, W., et al. Interactive effects of MC1R and OCA2 on melanoma risk phenotypes. Human Molecular Genetics, vol. 13, no. 4, p. 447-461, 2004.
GARCIA-BORRON, JC, SANCHEZ-LAORDEN, BL, JIMENEZ-CERVANTES, C. Melanocortin-1 receptor structure and functional regulation. Pigment Cell Research, vol. 18, no. 6, p. 393-410, 2005.
HEALY, E. Melanocortin 1 receptor variants, pigmentation, and skin cancer susceptibility. Photodermatology, Photoimmunology & Photomedicine, v. 20, no. 6, p. 283-288, 2004.
LANDI, MT, BAUER, J., PFEIFFER, RM, et al. MC1R germline variants confer risk for BRAF-mutant melanoma. Science, vol. 313, no. 5786, p. 521-522, 2006.
MUN, Y., KIM, W., SHIN, D. Melanocortin 1 Receptor (MC1R): Pharmacological and Therapeutic Aspects. International Journal of Molecular Sciences, vol. 24, no. 15, 2023.
Dr. Fabiano de Abreu Agrela Rodrigues MRSB holds a post-PhD in Neuroscience and is an elected member of Sigma Xi – The Scientific Research Honor Society (more than 200 members of Sigma Xi have received the Nobel Prize), as well as being a member of the Society for Neuroscience in the United States, the Royal Society of Biology and The Royal Society of Medicine in the United Kingdom, the European Society of Human Genetics in Vienna, Austria, and the APA – American Philosophical Association in the United States. He holds a Master’s degree in Psychology and a Bachelor’s degree in History and Biology. He is also a Technologist in Anthropology and Philosophy, with several national and international degrees in Neuroscience and Neuropsychology. Dr. Fabiano is a member of prestigious high IQ societies, including Mensa International, Intertel, ISPE High IQ Society, Triple Nine Society, ISI-Society, and HELLIQ Society High IQ. He is the author of more than 300 scientific studies and 30 books. He is currently a visiting professor at PUCRS in Brazil, UNIFRANZ in Bolivia and Santander in Mexico. He also serves as Director of CPAH – Centro de Pesquisa e Análises Heráclito and is the creator of the GIP project, which estimates IQ through the analysis of genetic intelligence. Dr. Fabiano is also a registered journalist, having his name included in the book of records for achieving four records, one of which is for being the greatest creator of characters in the history of the press.