HERC2 rs1667255: What Your Genotype Means
The rs1667255 variant is a single nucleotide polymorphism located within the HERC2 gene. It is part of a complex regulatory region that influences the expression of the nearby OCA2 gene, which is a primary determinant of human iris pigmentation.
What each genotype means
Associated with brown eyes
This genotype is strongly associated with brown iris pigmentation in European populations. It is located in a regulatory region of the HERC2 gene that influences the expression of the OCA2 gene, which is essential for melanin production in the eye.
This genotype is common in many global populations but is less frequent in individuals of Northern European ancestry.
Intermediate pigmentation profile
Carrying one copy of each allele may result in an intermediate phenotype regarding iris pigmentation. Research indicates that the HERC2-OCA2 locus acts as a major contributor to eye color variation, though individual outcomes are influenced by multiple genetic and environmental factors.
This heterozygous genotype is found at varying frequencies across populations, particularly in groups with mixed ancestral backgrounds.
Associated with blue eyes
This genotype is strongly associated with blue iris pigmentation in European populations. It is linked to a reduction in the activity of the OCA2 promoter, which leads to decreased melanin production in the iris.
This genotype is most common in populations of European ancestry and is relatively uncommon in African and East Asian populations.
Understanding the HERC2-OCA2 Locus
The rs1667255 variant is situated within the HERC2 gene, specifically on chromosome 15. While HERC2 encodes a protein involved in cellular protein degradation, this specific region of the gene is best known for its role as a regulatory hub. Research has established that the HERC2-OCA2 locus is the most significant genetic region influencing human eye color variation. The variant sits in a highly conserved genomic area that acts as an enhancer, controlling how much OCA2 protein is produced in the iris. Because OCA2 is essential for the production of melanin—the pigment that gives eyes their brown color—variations in this regulatory region can lead to reduced melanin production, which is associated with lighter eye colors like blue.
The Science of Eye Color Variation
Human eye color is a polygenic trait, meaning it is influenced by multiple genetic variants. The HERC2-OCA2 region is the primary driver of the distinction between blue and brown eyes. While rs12913832 is the most frequently cited SNP in this region, rs1667255 is also located within this critical regulatory landscape. These variants do not change the protein structure of HERC2 itself; instead, they alter the efficiency of the genetic switch that turns the OCA2 gene on or off. When this switch is less active, the iris produces less pigment, resulting in a blue appearance. It is important to note that while these variants have a strong statistical association with eye color, they are not the only factors involved, as other genes like SLC24A5 and IRF4 also contribute to the final phenotype.
Evidence and Research Context
The evidence linking the HERC2-OCA2 region to eye pigmentation is robust, supported by numerous genome-wide association studies (GWAS). However, the specific contribution of individual SNPs like rs1667255 is often studied as part of a larger haplotype—a group of variants inherited together. Because these variants are physically close on the chromosome, they are often linked, making it difficult to isolate the exact effect of one single SNP. Current research indicates that while the association with blue versus brown eye color is statistically significant, the predictive power of any single variant is limited. Scientists use these markers to understand the genetic architecture of pigmentation, but they caution that eye color prediction based on genetics alone remains an area of ongoing study rather than a definitive diagnostic tool.
Population Frequency and Distribution
The frequency of variants in the HERC2-OCA2 region varies significantly across global populations. The alleles associated with lighter eye pigmentation are most common in European populations, where they have been subject to specific evolutionary pressures. In contrast, these variants are relatively uncommon in African and East Asian ancestries, where brown eye color is the predominant phenotype. For rs1667255 specifically, the minor allele frequency is approximately 0.21 in European populations. This distribution highlights that eye color genetics are deeply tied to ancestral history. Researchers studying these frequencies emphasize that genetic markers identified in one population may not have the same predictive value or frequency in another, underscoring the importance of considering ancestry when interpreting genetic data.
What This Information Means for You
Understanding your genotype for rs1667255 provides insight into the genetic factors that contribute to your physical traits, specifically iris pigmentation. However, it is important to recognize that this information is for educational purposes only. Genetic variants in the HERC2 gene are not medical markers; they do not diagnose health conditions or predict future medical outcomes. You cannot change your genotype, and having a specific variant does not imply any health advantage or risk. If you are curious about your genetic makeup, treat this information as a window into your ancestral history and the biological mechanisms that make humans diverse. Always consult with a qualified genetic counselor if you have questions about how your genetic information relates to your personal health or family history.
How common is this variant?
The rs1667255 variant has a minor allele frequency of approximately 0.21 in European populations and is considered uncommon in African and East Asian ancestries.
Frequently asked questions
Can this SNP predict my exact eye color?
No, this SNP cannot predict your exact eye color. While it is associated with the blue versus brown eye color spectrum, eye color is a complex trait influenced by many genes and environmental factors.
Is this variant linked to any diseases?
The HERC2-OCA2 region is primarily associated with normal pigment variation. While OCA2 mutations can cause oculocutaneous albinism, the common regulatory variants like rs1667255 are not considered disease-causing.
Why do my eyes not match my genotype?
Eye color is polygenic, meaning many different genes contribute to the final result. If your genotype suggests one color but your eyes are another, it is likely due to the influence of other pigment-related genes not captured by this single SNP.
Should I be concerned about my HERC2 genotype?
No, there is no reason for concern. This variant is a normal part of human genetic diversity and is simply a marker for physical traits like eye color.
Sources & further reading
Educational information only, last refreshed 9/15/2026. Not medical advice — these associations describe population statistics, not individual predictions.
Curious what your genotype is for rs1667255?
Upload a raw DNA file from 23andMe, AncestryDNA, MyHeritage, or FamilyTreeDNA and see this variant — plus thousands more — interpreted in your full report.
Get my report — $29Related variants in HERC2
This variant is located in an intron of HERC2 and acts as a major regulatory marker for OCA2 expression, strongly influencing human eye color variation.
A well-documented marker in the HERC2/OCA2 region strongly associated with blue vs. brown eye color variation.
Intronic regulatory modifier in HERC2 acting as an enhancer upstream of OCA2 to fine-tune human iris pigmentation and hair shade traits.
A non-coding variant in the HERC2 regulatory region that modulates OCA2 expression and eye color.
Strongly determines human eye color; the C allele is associated with blue eye color and the T allele with brown eye color via long-range regulation of the OCA2 promoter.
Regulatory SNP in HERC2 that modulates OCA2 expression, serving as a primary determinant of human eye color.