OCA2 rs6056126: Eye Color and Pigmentation Genetics
rs6056126 is an intronic single nucleotide polymorphism located in the OCA2 gene on chromosome 15. Research links this variant to human eye color variation and subtle differences in visible facial pigmentation traits. As a non-coding marker within a key melanin-pathway gene, it represents a modest modifier rather than a standalone determinant of physical appearance.
What each genotype means
Typical pigmentation profile
This genotype is associated with standard pigmentation patterns in the OCA2 gene region. Research indicates that this variant contributes to the complex genetic architecture influencing human eye and skin color, though it is one of many factors involved.
This is the most common genotype in many global populations, though frequencies vary significantly by ancestry.
Intermediate pigmentation association
Carrying one copy of the T allele is associated with subtle variations in pigmentation traits. Because eye and skin color are polygenic traits, this genotype represents a minor contribution to your overall appearance profile.
This heterozygous genotype is found in a significant portion of the population, particularly among individuals of European ancestry.
Associated with pigmentation variation
The T allele at this position is statistically associated with variations in eye color shade and facial pigmentation. While this marker is linked to pigmentation, it does not determine your appearance in isolation, as many other genetic and environmental factors play a role.
The T allele is carried by roughly 1 in 6 people of European ancestry, making this specific homozygous genotype less common than the others.
What Is rs6056126 and Where Is It Located?
The single nucleotide polymorphism rs6056126 is a common non-coding variant positioned in an intron of the OCA2 gene on the long arm of human chromosome 15. Because it resides in an intronic segment rather than a protein-coding exon, rs6056126 does not directly alter the amino acid sequence of the resulting protein. Instead, variants in intronic regions often exert their effects by influencing transcriptional regulation, alternative splicing, or by serving as inherited proxies in linkage disequilibrium with nearby regulatory elements. Modern genomics categorizes rs6056126 as a common polymorphism that naturally varies across global populations without disrupting core cellular viability.
The Biological Role of the OCA2 Gene
The OCA2 gene provides essential instructions for producing the P protein, an integral transmembrane transporter situated within melanosomes. Melanosomes are specialized intracellular compartments within melanocytes responsible for synthesizing and storing melanin, the primary pigment governing hair, skin, and iris coloring. Research indicates that the P protein acts as an anion channel, regulating the internal pH and ion homeostasis of melanosomes to optimize enzymatic tyrosinase activity. Disruptive mutations in both copies of the OCA2 gene lead to oculocutaneous albinism type 2 (OCA2), whereas subtle common variants across the locus modulate baseline melanin density and iris pigmentation.
Research Evidence on Eye Color and Facial Pigmentation
Genome-wide association studies (GWAS) and human pigmentation mapping cohorts have linked rs6056126 to nuances in eye color and facial pigmentation characteristics. The scientific evidence supporting this association is rated as moderate. Unlike the master regulatory switch rs12913832 in the adjacent HERC2 enhancer—which largely dictates the major blue-versus-brown dichotomy—variants like rs6056126 are thought to act as secondary modifiers. They explain additional phenotypic variance in iris shade, such as intermediate green, hazel, or nuanced dark-to-light gradients. Its impact is complex, polygenic, and context-dependent, often interacting with other pigment loci across the genome.
Understanding Ancestry and What This Information Means
Population genetics data demonstrates that allele frequencies for rs6056126 differ significantly across ancestral groups. In European-ancestry reference cohorts cataloged in gnomAD, the minor T allele appears at an estimated frequency of approximately 0.16, whereas other continental populations show distinct distribution patterns. It is crucial to understand that direct-to-consumer genotyping of rs6056126 cannot definitively predict your exact eye color or skin tone. Human appearance is a classic polygenic trait shaped by dozens of genes—including HERC2, MC1R, SLC24A5, and TYR—acting in concert. Furthermore, this variant is purely benign and carries no known direct medical or disease risk.
How common is this variant?
The minor T allele occurs at a frequency of approximately 0.16 (16%) in European populations according to gnomAD data. Frequencies for rs6056126 vary across other global ancestral groups, where the C allele remains the predominant ancestral state.
Frequently asked questions
Can rs6056126 tell me my exact eye color?
No, rs6056126 cannot tell you your exact eye color on its own. Human eye color is a polygenic trait governed by multiple cooperating loci, particularly the major HERC2-OCA2 regulatory switch. rs6056126 acts only as a minor modifier of eye color shade.
Does this genetic variant cause albinism?
No, rs6056126 does not cause albinism. Oculocutaneous albinism type 2 requires severe, loss-of-function pathogenic mutations in both copies of the OCA2 gene. rs6056126 is a harmless, common non-coding variant that naturally occurs in healthy populations.
Is rs6056126 associated with any health conditions or diseases?
No direct disease associations are established for rs6056126. It is primarily studied in the context of visible appearance traits such as iris and facial pigmentation, and it carries no recognized clinical risk.
Why do some people with the same genotype have different eye colors?
Eye color is determined by the cumulative influence of many genetic variants acting together, along with microscopic structural factors in the iris stroma that scatter light. Because rs6056126 contributes only a small fraction of the total genetic variance, individuals with the same genotype can easily have different eye colors.
Sources & further reading
Educational information only, last refreshed 9/8/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This missense variant (p.Ala486Thr) in the OCA2 gene is associated with human pigmentation traits, including eye and skin color variation.
This variant is located within the OCA2 gene, which encodes the P protein essential for melanin production and is a key locus for human pigmentation variation.
Missense variant Arg419Gln strongly linked to intermediate eye color, blue/green iris phenotypes, and lighter pigmentation.
Pigmentation-modifying SNP modulating blue versus brown eye color penetrance and melanin deposition.
Functional non-synonymous variant (Arg419Gln) in OCA2 linked with ancestral pigmentation divergence and lighter eye/skin color.
Common missense variation (Arg305Trp) in OCA2 associated with eye color gradation and lighter skin pigmentation in European populations.