Let's talk about Eye Colour & Genetics
Eye colour is can be a striking feature, so it’s no surprise people write songs and poetry celebrating someone’s eye colour. Whether or not you believe eyes are the window to the soul, eye colour is a genetic trait that has interesting things to say about your DNA.
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.
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.
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.