Why do humans have darker eyes with dark skin

Nischler C, Michael R, Wintersteller C, et al. Skin color is determined not by how many melanocytes someone has (were all born with a similar amount), but rather by how active the cells are. Waardenburg syndrome: Medlineplus genetics. Genotype–phenotype associations and human eye color. What color are newborns' eyes? Prevalence of iris colour in the Newborn Eye Screening Test (NEST) study. Ludwig CA, Callaway NF, Fredrick DR, Blumenkranz MS, Moshfeghi DM. The role of melanin in protecting the skin and the retina from light damage: A comparative biological framework for age-related macular degeneration. Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow on Twitter for your daily dose of fun science facts.Thien K, Schachter J, Quigley MG. The light reflected back gives the eyes a bluer colour. In their eyes, light passes through the anterior border and interacts with grey cells further into the iris.

Fairer skinned people produce less melanin. So a person with dark skin also has darker, browner eyes.

It's the same pigment that determines skin colour and the more we produce, the darker the colour. Until recently, researchers assumed that after human ancestors shed most body hair, sometime before 2 million years ago, they quickly evolved dark skin for protection from skin cancer and other harmful effects of UV radiation. Everybody has roughly the same amount of melanocytes but our genes determine how much of a pigment, called melanin, they produce. This contains pigment-producing cells called melanocytes. The outer two are collectively known as the anterior border.

The iris, located behind the cornea (the eye's outermost layer), is itself made up of multiple layers. Why do our eyes come in different colours?Īs with our skin, eye colour is determined by pigmentation.

Why do humans have darker eyes with dark skin