![]() ![]() Regarding connections between eye colour and eye diseases, research has shown darker iris colour is associated with an increased risk of cataract and a reduced risk of ocular uveal melanoma (a form of eye cancer), compared with blue eyes. Melanin in the iris of the eye appears to help protect the back of the eye from damage caused by UV radiation and high-energy visible ("blue") light from sunlight and artificial sources of these rays.īecause blue eyes contain less melanin than green, hazel or brown eyes, they may be more susceptible to damage from UV and blue light. So don't be concerned if your child begins to lose that "baby blue" eye colour and their eyes become green, hazel or brown as they get a little older. Because of this, many babies have blue eyes, but their eye colour changes as the eye develops during early childhood and more melanin is produced in the iris. The human eye does not have its full adult amount of pigment at birth. Blue eyes at birth doesn't mean blue eyes for life But her brother, Prince George, has very brown eyes.) 4. (Here's a royal example of the unpredictability of eye colour: Princess Charlotte, the young daughter of blue-eyed Prince William and green-eyed Kate Middleton, has blue eyes. Even if you and your partner both have blue eyes, that's no guarantee your child's eyes will also be blue. So it's impossible to know for sure if your children will have blue eyes. Also, the anatomic structure of the iris can affect eye colour to some degree. You can't predict the colour of your child's eyesĪt one time, it was believed that eye colour - including blue eyes - was a simple genetic trait, and therefore you could predict a child's eye colour if you knew the colour of the parents' eyes and perhaps the colour of the grandparents' eyes.īut geneticists now know that eye colour is influenced by as many as 16 different genes to some degree - not just one or two genes as once thought. Brown eyes have the highest amount of melanin in the iris, and blue eyes have the least. There's only brown pigment in the eye - there is no hazel pigment or green pigment or blue pigment. The colour of our eyes depends on how much melanin is present in the iris. Melanin is a brown pigment that controls the colour of our skin, eyes and hair. Blue eyes don't have blue pigmentĪs mentioned above, blue eye colour is determined by something called melanin. One theory is that blue eyes were immediately considered an attractive feature, causing people to seek mates with blue eyes to have children with, enabling the genetic mutation to multiply. So if blue eyes are the result of a genetic mutation in a single individual, how did the trait spread from just one person to being present in 20 to 40 percent of the populations of some European countries today? "They have all inherited the same switch at exactly the same spot in their DNA." "From this we can conclude that all blue-eyed individuals are linked to the same ancestor," said Eiberg. ![]() Brown-eyed individuals, on the other hand, have considerable individual variation in the area of their DNA that controls melanin production. In addition to having significantly less melanin in their iris than people with brown eyes, hazel eyes or green eyes, blue-eyed individuals have only a small degree of variation in their genetic coding for melanin production. This genetic switch, located in the gene next to the OCA2 gene, limits the production of melanin in the iris - effectively "diluting" brown eyes to blue. "But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a 'switch', which literally turned off the ability to produce brown eyes."Įye colour depends on the amount of a single type of pigment (called melanin) in the iris of the eye. "Originally, we all had brown eyes," said Hans Eiberg, associate professor in the Department of Cellular and Molecular Medicine at the university and lead author of the study. ![]() It appears that a genetic mutation in a single individual in Europe 6,000 to 10,000 years ago led to the development of blue eyes, according to researchers at the University of Copenhagen. ![]() All blue-eyed people may have a common ancestor Here are a few facts about blue eye colour you might not know: 1. This is one reason why blue colour contact lenses are popular. Among human beings, blue eyes are less common than brown eyes. ![]()
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