MC1R rs1805007: What Your Genotype Means
The rs1805007 variant is a well-studied genetic change located within the MC1R gene. It is strongly associated with the development of red hair, fair skin, and specific pigmentation patterns in human populations.
What each genotype means
Typical MC1R function
This genotype represents the common, functional version of the MC1R gene. Individuals with this profile typically have standard pigmentation responses to sunlight and are not associated with the red hair phenotype linked to this specific variant.
This is the most common genotype in most global populations.
Carrier of red hair variant
Carrying one copy of the T allele (also known as R151C) may influence pigmentation, though it is often associated with a more modest effect on hair and skin color compared to having two copies. Research indicates that even single-copy carriers may have a slightly increased sensitivity to sun exposure, so it is advisable to maintain consistent sun protection practices.
This genotype is found at varying frequencies, particularly in populations of European ancestry.
Associated with red hair
This genotype is strongly associated with the red hair phenotype and fair skin due to reduced function of the melanocortin 1 receptor. Because this variant is linked to increased sensitivity to ultraviolet radiation, individuals with this profile should prioritize sun protection and discuss skin health monitoring with a dermatologist.
This genotype is most frequently observed in individuals of Northern European descent and is rare in other global populations.
Understanding the rs1805007 Variant
The rs1805007 variant is a single nucleotide polymorphism (SNP) located within the MC1R gene, which sits on chromosome 16. In scientific literature, this specific change is often referred to by its protein-level effect, p.Arg151Cys, or simply R151C. A SNP represents a variation at a single position in the DNA sequence. Because the MC1R gene is critical for determining how our bodies produce pigment, changes at this specific location can alter the function of the resulting protein. Researchers track this variant because it serves as a primary genetic marker for understanding the biological basis of human hair and skin color variation. By studying where this SNP sits in the genome, scientists have been able to map its influence on the melanocortin 1 receptor, a protein that acts as a switch for pigment production.
The Role of the MC1R Gene
The MC1R gene provides instructions for making the melanocortin 1 receptor, a protein primarily found on the surface of melanocytes. These specialized cells produce melanin, the pigment that gives color to our skin, hair, and eyes. The receptor functions like a biological switch: when activated, it encourages the production of eumelanin, a dark pigment that provides protection against ultraviolet (UV) radiation. When the receptor is less active or dysfunctional, the cell produces more pheomelanin, a lighter, reddish-yellow pigment that offers less protection from the sun. Variants like rs1805007 are known to reduce the receptor's ability to signal effectively. This shift in pigment production is the fundamental reason why certain genetic variations in this gene are so strongly linked to the red hair phenotype and a tendency toward fair, sun-sensitive skin.
Research and Evidence Strength
The evidence linking rs1805007 to red hair and fair skin is considered strong across the scientific community. Numerous studies have consistently identified this variant as a major contributor to the red hair phenotype. Research indicates that individuals who carry these variants often exhibit reduced receptor function, which correlates with lighter pigmentation. Beyond hair color, this variant has been investigated for its association with skin cancer risk, as the resulting decrease in protective eumelanin may influence how skin reacts to sun exposure. While the association with red hair is robust, it is important to note that pigmentation is a complex trait influenced by many genes. Therefore, while rs1805007 is a significant predictor, it does not act in isolation. Current research continues to explore how this variant interacts with other genetic factors to produce the wide spectrum of human skin and hair colors observed globally.
Population Frequency and Distribution
The frequency of the rs1805007 variant varies significantly across different ancestral populations. It is most commonly observed in populations of European descent, where it contributes to the prevalence of red hair and fair skin. Because human migration and genetic history have shaped the distribution of these alleles, the variant is not uniformly distributed worldwide. In some populations, the allele is rare or absent, while in others, it is a well-documented feature of the local genetic landscape. Researchers use large-scale genomic databases to track these frequencies, which helps in understanding the evolutionary history of human pigmentation. Because the variant is tied to specific physical traits that have been subject to different selective pressures in various environments, its presence serves as a fascinating example of how human genetic diversity is distributed across the globe.
Interpreting Your Genetic Information
If you have information about your rs1805007 genotype, it is important to understand what this means in a practical context. This variant is a trait-associated marker, meaning it provides information about physical characteristics like hair and skin color. It is not a diagnostic tool for medical conditions. While some studies suggest that variants in the MC1R gene may be associated with an increased risk of skin cancer due to sun sensitivity, this is a complex relationship influenced by many environmental and genetic factors. You cannot use this information to predict your health outcomes or to make medical decisions. If you have concerns about your skin health, sun sensitivity, or cancer risk, the most appropriate step is to consult with a dermatologist or a qualified healthcare provider. They can provide personalized advice based on your clinical history and physical examination, which are far more informative than a single genetic variant.
How common is this variant?
The rs1805007 variant is most frequently observed in populations of European ancestry, where it is a primary genetic contributor to red hair and fair skin phenotypes.
Frequently asked questions
Is rs1805007 a cause of skin cancer?
The variant is associated with fair skin and sun sensitivity, which are risk factors for skin cancer. However, it is not a direct cause of cancer, and many environmental factors play a much larger role in skin health.
Can I use this variant to predict my child's hair color?
While rs1805007 is a strong predictor of red hair, hair color is a polygenic trait influenced by many different genes. A single variant cannot provide a definitive prediction for a child's appearance.
Does having the TT genotype mean I will definitely have red hair?
While the TT genotype is strongly associated with red hair, it is not a guarantee. Other genetic and environmental factors also influence the final expression of hair color.
Should I get tested for MC1R variants?
Genetic testing for pigmentation traits is generally not medically necessary. If you are concerned about sun sensitivity or skin health, you should speak with a dermatologist rather than relying on genetic testing.
Sources & further reading
Educational information only, last refreshed 10/5/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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The p.Arg163Gln variant in MC1R is associated with red hair, fair skin, and increased melanoma risk.
This missense variant (p.Arg142His) is a well-established, highly penetrant allele associated with red hair color and fair skin pigmentation.
This missense variant (p.Arg160Trp) is a primary genetic determinant of red hair color, pale skin, and increased freckling in European populations.
The Val60Leu missense variant in MC1R is a well-documented factor contributing to the red hair, fair skin, and freckling phenotype.
A rare variant associated with lighter skin pigmentation in specific populations.
Asp294His coding substitution in the MC1R gene associated with red hair, skin sun-sensitivity, and melanoma risk.