People with a lot of melanin are more likely to have brown eyes, whereas those with little of it will probably have blue or green eyes. Here are five other interesting facts about eye colour.
1. Everyone’s eyes are brown
Or at least the melanin in their irises is brown. What makes someone’s eyes look a different colour depends on how much light is absorbed by the melanin.
2. You can have different-coloured eyes
Known as heterochromia, you can either be born with this condition or develop it later in life.
3. All blue-eyed people share a common ancestor
This person would have had brown eyes but carried the first genetic mutation for blue eyes, which was then passed down and spread over many generations.
4. Eye colour affects your sensitivity to light
If your eyes are particularly sensitive to the sun, this may be because of their colour. Since blue and green eyes have less melanin, they’re not as effective at blocking out harsh sunlight and UV rays
5. Predicting eye colour is harder than you think
Despite the popular belief about dominant and recessive genes, you can’t predict a baby’s eye colour just by looking at the eyes of the parents. Eye colour is actually a multi-gene trait determined by a combination of up to 16 genes.