Question: How come some people have 2 different coloured eyes. Eg one blue one green ?

Remsha Afzal answered on 16 Nov 2018:

Great question! the condition is called heterochromia! Eye color is a polygenic trait which means that multiple genes control its expression in people. Heterochromia is a rare thing to happen but they result from more or less pigmentation in the two eyes due to different expression pattern of genes controlling eye color.