11th March 2021

The genetics of human eye colour is much more complex than previously thought, according to a new study published today.

An international team of researchers led by King’s College London and Erasmus University Medical Center Rotterdam have identified 50 new, previously unknown genes for eye colour in the largest genetic study of its kind to date. The study, published in Science Advances, involved the genetic analysis of almost 195,000 people across Europe and Asia.

These findings will help to improve our understanding of eye diseases such as pigmentary glaucoma and ocular albinism, where eye pigment levels play a role.

In addition, the team found that eye colour in Asians with different shades of brown is genetically similar to eye colour in Europeans ranging from dark brown to light blue.

This study builds on previous research in which scientists had identified a dozen genes linked to eye colour, believing there to be many more. Historically, scientists thought that variation in eye colour was controlled by one or two genes only, with brown eyes dominant over blue eyes.

Co-senior author Dr Pirro Hysi, King’s College London, said:

 “These findings are exciting because they bring us to a step closer to predicting with a high degree of confidence the colour of the eyes based on DNA information alone. In certain circumstances, that could allow parents to predict the eye colour of their future children, based on the parents’ genetics. But these findings will also be important and tremendously improve our understanding of many diseases that we know are associated with specific pigmentation levels.”

Co-senior author Dr Manfred Kayser, Erasmus University Medical Center Rotterdam, said:

“Amongst other relevancies, this study delivers the genetic knowledge needed to improve eye colour prediction from DNA as already applied in anthropological and forensic studies, but with limited accuracy for the non-brown and non-blue eye colours.”