What HERC2 rs12913832 Means in Your 23andMe Raw Data
rs12913832 in 23andMe raw data is a major common eye colour marker; AA tends toward less iris melanin, AG is variable and can be blue, green, hazel, or brown, GG tends toward more iris melanin, but it cannot predict exact shade.
In a 23andMe raw file, rs12913832 appears as a single A/G call in the HERC2 region of chromosome 15. It is a major common marker for eye colour in people of European ancestry. For people of European ancestry, the short version is: AA tends toward less iris melanin, AG is variable and can be blue, green, hazel, or brown, and GG tends toward more iris melanin. This call predicts melanin tendency, not an exact shade.
What does rs12913832 mean in my 23andMe raw data?
Your raw file does not say blue eyes or brown eyes. It shows a genotype at a specific position on chromosome 15. In supported raw exports, this marker usually appears as AA, AG, GG, or a no-call if the chip did not read it cleanly. The A/G letters here are the supported 23andMe export convention. Other strand builds or third-party reports may show the complement letters instead. This article does not advise manual allele flipping.
For people of European ancestry, the usual pattern is:
| 23andMe call | Usual tendency | Why |
|---|---|---|
| AA | Blue, grey or very light eyes | Two low-pigment copies. Lower OCA2 expression. |
| AG | Variable; can be blue, green, hazel or brown | One higher-pigment copy can increase melanin, but the single SNP does not reliably predict shade. |
| GG | Brown, often darker brown | Two higher-pigment copies. More iris melanin. |
Scroll the table sideways for the rest →
What your 23andMe raw call tends to mean in European ancestry. This is a tendency, not a promise.
The common mistake is to read AG as hazel or AA as definitely blue. A single SNP gives a probability, not a paint swatch.
How HERC2 rs12913832 changes eye colour
HERC2 and OCA2 sit close together on chromosome 15. OCA2 makes a protein involved in producing melanin, the pigment that darkens eyes, skin and hair. rs12913832 is not in the part of HERC2 that codes for a protein. It sits in a control region that acts on OCA2.
The A form is associated with lower OCA2 expression in iris melanocytes. The G form is associated with higher expression. More OCA2 activity means more melanin in the iris. Less means less melanin. Blue eyes are not blue pigment. They are a low-melanin iris scattering light.
rs12913832 does not make eye colour. It tunes a switch that controls OCA2, the gene that loads the iris with melanin.
The flow below is illustrative. It shows a tendency, not a one-to-one rule.
Why your raw file says AA, not blue eyes
A raw DNA file is a list of measured calls, not a phenotype report. The same genotype can look different depending on ancestry and other genes. A raw call alone is not a phenotype. If your raw file says AA, the finding is less iris melanin likely, not blue.
Why this SNP cannot predict your exact eye shade
Eye colour is polygenic. HERC2/OCA2 is the major axis in Europeans, but other genes such as SLC24A5, SLC45A2, TYR, TYRP1 and IRF4 shift the final shade. Hazel, green and amber eyes often come from intermediate melanin plus iris structure and lighting.
The table above is for European ancestry. Outside that group, the same genotype says much less. In many African, East Asian and South Asian populations, the G form is common and eye colour is still brown, because other pigmentation variants dominate. An A/G call cannot override that background.
What you can reasonably take from the result is directional. AA points toward less iris melanin. GG points toward more. AG is variable and can overlap lighter and darker outcomes. It does not tell you if your eyes will photograph green, grey or hazel, and it cannot time when a baby's eyes will settle.
What to do with this result
Eye colour is interesting but not medically actionable. If you are looking at other inherited traits, the same raw file has more to say.
The download steps for 23andMe, on the page itself.
The short version: what is worth acting on, first.
HealthOS has a free DNA tool at https://healthosx.com/dna. The DNA story needs no account. It reads 23andMe, AncestryDNA, MyHeritage, FamilyTreeDNA, Living DNA, WeGene and whole-genome VCFs. The trait and health report runs in your browser. The listed HealthOS finding is HERC2 / OCA2: Your eye colour, predicted from scratch; this is a prediction, not an exact shade. Trait reporting needs rsIDs, so a whole-genome VCF without rsIDs gets ancestry only. Ancestry reporting is optional and uses a server. Only the markers needed for ancestry are sent, and those markers are deleted afterwards unless you choose to keep them.
New to raw DNA files? Start with the full guide: How to Download & Analyze Your 23andMe Raw Data Free
Written by
HealthOS Research