Let's talk aboutEye Colour & Genetics

How it works

We get our eye colour from a type of pigment called melanin. Melanin also determines the colour of our skin and hair. People who have a lot of a black- or brown-coloured type of melanin called eumelanin in the front layers of the iris will probably have darker eyes. Eumelanin is good at absorbing light, which gives it its darker colour. People with blue eyes have much less of this pigment in their eyes.

The genetic link

Eye colour is a complex genetic trait because multiple genes are involved. One of the most important genetic factors is a marker near a gene called OCA2 that affects how much brown pigment your cells produce, and thus how much brown pigment is in your eyes.

Did you know?

Our ancient ancestors had brown eyes. But at some point in history, a baby was born with a genetic variant leading to a new eye colour: blue. Most light-eyed people carry that same genetic variant to this day.

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What’s the genetic story behind your eye colour? 23andMe’s Health + Ancestry Service can help you find out. Pick up one of our kits and we’ll tell you what your genetics have to say about your eye colour.

References

Beleza S et al. (2013). “Genetic architecture of skin and eye colour in an African-European admixed population.” PLoS Genet. 9(3):e1003372.

Eiberg H et al. (2008). “Blue eye colour in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression.” Hum Genet. 123(2):177-87.

Hirobe et al. (2011.) “The mouse pink-eyed dilution allele of the P-gene greatly inhibits eumelanin but not pheomelanin synthesis.” Pigment Cell Melanoma Res. 24;241-6.

Larsson M et al. (2011). “GWAS findings for human iris patterns: associations with variants in genes that influence normal neuronal pattern development.” Am J Hum Genet. 89(2):334-43.

Lewis RA. (2003). “Oculocutaneous Albinism Type 2.” GeneReviews.

Liu F et al. (2009). “Eye colour and the prediction of complex phenotypes from genotypes.” Curr Biol. 19(5):R192-3.

Liu F et al. (2010). “Digital quantification of human eye colour highlights genetic association of three new loci.” PLoS Genet. 6(5):e1000934.

Peshek D et al. (2011). “Preliminary evidence that the limbal ring influences facial attractiveness.” Evol Psychol. 9(2):137-46.

Prota G et al. (1998) “Characterization of melanins in human irides and cultured uveal melanocytes from eyes of different colours.” Exp Eye Res. 67:293–9.

Sturm RA and Frudakis TN. (2004). “Eye colour: portals into pigmentation genes and ancestry.” Trends Genet. 20(8):327-32.

U.S. National Library of Medicine. (2018). “Is Eye Colour Determined by Genetics?” Genetics Home Reference.