Edmund has spent the last ten years working in clinical research. He has written many articles on human anatomy and physiology.
Is Eye Color Static?
While gazing into a baby’s eyes, one often wonders whether those icy blue eyes will one day change to another color.
The Colored Ring of the Eye
Eye color is displayed by a ring-shaped structure inside the eyeball, the so-called Iris. The tissue of the iris contains a brown pigment called melanin. The amount of melanin in the iris varies a lot from person to person. The more melanin a person has, the darker his eyes are.
Brown eyes have a lot more melanin than green eyes, which in turn have more than blue eyes. Melanin production can be further diminished in some individuals and completely absent in albinos.
The Eyes of a Newborn
The eyes of a newborn baby usually appear blue because the baby has a very low melanin concentration. At this early stage, the baby's genetically assigned eye colors haven't been expressed yet.
There is neither a blue nor a green pigment in the eye, the blue eye color is due to the way light gets scattered inside the iris together with the low melanin concentration. This is a similar effect to that which makes a cloud-free sky appear blue.
So, When Does the Change Happen?
Babies' eyes change color about six to nine months after birth. This is usually when melanin production starts inside the eyeball.
A one-year-old with darkly pigmented eyes might have been born with blue eyes. Eye color change in babies is usually from a lighter to a darker shade. Don't expect your baby's brown eyes to change back to blue – it most likely will not happen naturally.
The amount of melanin in the eye is determined by genetics. The majority of us end up with brown eyes because our genes code for the production of a lot of melanin. Those who grow up to have blue eyes have genes that code only for a small amount of melanin; hence they retain their blue eyes.
Both Parents Have Brown Eyes. Why Does the Baby Have Blue Eyes?
There is a good explanation for this. But let’s check out some interesting polls first.
About the polls:
The aim of the first poll below is to see how many percent of you guys have a different eye color from your parents. The next poll is for those with kids. Let’s see if you have at least one child whose eye color differs from yours and your partner’s.
Could Your Wife Have Cheated?
This is one of those questions that frequently cross the mind of a guy who suspects his wife of infidelity.
Mother Nature provides countless possibilities when it comes to the genetics of eye color, such that eye color cannot be used to determine who the father of a child is. If you have no other reason to suspect infidelity then your child is most likely yours.
I expect the results of the above polls to show that at least some of us have a different eye color from our parents.
Eye color inheritance is a complex issue but below is an easy-to-read explanation.
Eye Color Inheritance
People used to think that if both parents had blue eyes, they could never bear a child with brown eyes; science has disproven this numerous times in recent years.
We now know that eye color is determined by a complex interaction of several genes. These interactions have given rise to a wide range of eye colors in the world. Scientists have managed to track down a number of these genes. A gene called OCA2 is one of the key players. OCA2 provides the recipe for melanin production in the iris .
When your body makes new cells, DNA is copied from existing cells to the new ones. Every now and then an error may occur in the DNA-copy process. This error is called Single Nucleotide Polymorphism (SNP). SNP causes genetic variations between you and everyone else.
Genetic variations can increase or limit the action of OCA2. Genetic variations together with the interaction of genes give each one of us a unique recipe to produce melanin. OCA2 is totally shut down in albinos, resulting in melanin deficiency.
Families with blue-eyed parents have been studied in the past to see how many brown-eyed children they had . As expected, it was found that many blue-eyed parents gave birth to some brown-eyed children.
So if you and your wife both have blue eyes, and your kids end up having green eyes, don’t confront the milkman.