Even if you and your partner both have blue eyes, that's no guarantee your child's eyes will also be blue. This BiologyWise article provides an understanding of mutations and their effects. For all those brunettes wishing they were naturally blond, a small genetic change could have made all the difference. 201 S. Market St. How do you know if a new-born baby needs glasses? This blue color is made by light scattering when it hits blue eyes (or the sky or ocean!). But 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. 1, 2014 , 1:15 PM. Because our appearance is so strongly influenced by the color of our skin and hair, geneticists have long sought to understand the genetic bases of these traits and when they evolved. If two parents have different complexions, these genes can get mixed around a bit. © 2020 American Association for the Advancement of Science. So it's impossible to know for sure if your children will have blue eyes. That SNP caught the eye of David Kingsley, an evolutionary geneticist at Stanford University in California. In northern Europeans, the closest gene to an SNP that was strongly linked to blondness was KITLG, which codes for a protein that is key to making sure cells go to their proper places in the body and specialize accordingly. When talk about blonde hair and blue eyes we always think about the European. Eye allergies: Treatment for the relief from itchy and watery eyes, Conjunctivitis: Causes and symptoms of pink eye. The Genetics of Blond Hair By Elizabeth Pennisi Jun. Federal ID # 94-2864660. “It’s a ‘turn the switch down.’ ”. Brown-eyed individuals, on the other hand, have considerable individual variation in the area of their DNA that controls melanin production. (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. Still, because many people with blue eye colour are sensitive to light and may have more risk of damage to their retinas from UV light, most opticians recommend that people with blue eyes should be extra cautious regarding their exposure to sunlight. Melanin is a brown pigment that controls the colour of our skin, eyes and hair. In any given species, the genetic makeup is uniform across a population. Like it? That makes the link between lighter eyes, hair, and skin tighter. When he and his colleagues studied this regulatory DNA in human cells grown in a laboratory dish, they discovered that the blond-generating SNP reduced KITLG activity by only about 20%. Some of those base changes, or single-nucleotide polymorphisms (SNPs), were in genes involved in the production of pigments, such as melanin. The human eye does not have its full adult amount of pigment at birth. Other SNPs lay outside genes but could be part of the regulatory DNA that helps control the function of genes nearby. “We had a choice,” Kingsley recalls. researchers at the University of Copenhagen, A study of European Americans with blue eyes, Stye treatment: How to get rid of a stye with home remedies. Click here to learn more about some rare eye colors. It’s still possible to get a combination of shades of hair, eyes, and skin, but it’s less likely. Its content is solely the responsibility of the authors and does not necessarily represent the official views of Stanford University or the Department of Genetics. And since melanin can absorb light, they look even darker! Also, the anatomic structure of the iris can affect eye colour to some degree. 1, 2014 , 1:15 PM For all those brunettes wishing they were naturally blond, a small genetic change could have made all the difference. But her brother, Prince George, has very brown eyes.). But it's not only European that have the blue eyes, a tribe in Indonesia do have a pair of beautiful blue eyes too!The Buton tribe is one of the tribes in Indonesia, precisely in the province of Southeast Sulawesi Eye allergies: Relief for itchy and watery eyes, How to get rid of a stye: Treatments and remedies, Glaucoma treatment: Drugs, drops and more, Computer eye strain: 10 tips to get relief, Digital devices and children: Protecting their eyes, Hyperopia (long sightedness): How to correct for it. It is generally believed that all human beings share approximately 98 percent of their genetic makeup. AAAS is a partner of HINARI, AGORA, OARE, CHORUS, CLOCKSS, CrossRef and COUNTER. Share it! Green eyes have some brown pigment that absorbs some of the light and scatters the rest 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. This is the same way that the sky and water aren’t actually blue, even though it appears that way to us. The human eye does not have its full adult amount … Blue eyes and blond hair are linked together, How scientists can figure out the eye and hair color of people living 1000s of years ago by looking at their DNA, Blond hair and blue eyes are linked It turns out blue eyes aren’t actually colored blue! We encourage our readers to consider supporting these humanitarian eye care non-profit organizations. 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. And an iris that has some melanin will absorb some light and scatter the rest, making it appear green. Well this gets into why we only see brown, blue, and green eyes (typically). A study of European Americans with blue eyes found people with these characteristics had up to 83 percent higher odds of becoming dependent on alcohol, compared with matched controls who had darker eye colour. If one parent has a darker complexion and the other has a lighter complexion, then their children could have a mix of light or dark hair, eyes, and skin. Here are a few facts about blue eye colour you might not know: 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. Changes in that regulatory DNA could result in hair color but not skin color change, or vice versa, because regulatory DNA can change gene activity in just certain parts of the body. You’ve probably noticed that all people in certain regions of the world tend to either have lighter or darker skin, hair, and eyes (complexions). Contacts for teens: What age can you wear contacts? Imagine if there was a region where most people had lighter complexions. “This study provides solid evidence” that this switch regulates the expression of KITLG in developing hair follicles, says Fan Liu, a genetic epidemiologist at Erasmus MC in Rotterdam, the Netherlands, who was not involved with the work. AR coating is recommended for all types of glasses lenses — including single vision, bifocal and progressive lenses — to eliminate distracting reflections and allow people to see the beauty and expressiveness of your eyes. Skin color also often fits in this trend: people with lighter hair and skin often have light eyes. Facts about sunglasses: A FAQ and buying guide, Polarised sunglasses: Best for reducing glare, Designer and fashion sunglasses: Look like a celebrity, Non-prescription sunglasses: What to know before buying, Buying kids' sunglasses? Your eyes can’t make a blue pigment, so why do we see different colors? Yet it is bracketed by sections of regulatory DNA, any one of which may take control in a different tissue. The iris of your eye (the colored part) is where melanin can be found. Yes, it is! There’s another layer to this. In one variant, they left the blond-generating SNP intact; and in the other variant, they changed that SNP to another base, so that the DNA looked like it does in brunettes. turned off the ability to produce brown eyes.". “This isn’t a ‘turn the switch off,’ ” Kingsley says. Eye colour depends on the amount of a single type of pigment (called melanin) in the iris of the eye. Liz is a senior correspondent covering many aspects of biology for Science. This is why people typically have either all light features, or all dark features. To learn whether that SNP was part of the regulatory DNA for human KITGL, Kingsley’s team turned to mice. Currently, there is no accepted theory regarding the true origins of blond hair. So that’s why you see people with blond hair typically have blue eyes! In each freshwater location, these fish were evolving independently, yet time and time again, changes in the regulation of this gene led to fairer or darker skin, depending on the murkiness of the water. These are responsible for hair color, eye color and blood type… Mutations in these genes typically change skin and hair color. Image from Flickr. 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. 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. If your melanocytes produce a lot of melanin, you’re likely to have darker skin, hair, and eyes. He and his colleagues had found that this gene was key to altering the coloration of fish called sticklebacks that had become isolated in freshwater rivers and lakes when glaciers receded.