Have you wondered about eyes of different colors and how do people inherit them? As you may have noticed, there are different people with different eye colors. These eye colors can vary from gray, hazel, blue, green, and brown.
But did you know that the color of the eyes is actually the color of the iris? There is a pigment known as melanin present in your iris that produces the color of your eyes. For example, blue eyes are produced due to a lack of melanin while brown eyes are produced by higher concentrations of melanin. The resulting eye color can be any shade that is further determined by genetics.
Here is a brief illustration of the color chart of the human eye.
Usually, both parents with green can end up with a green-eyed baby, but not always. Likewise, parents with two hazel eyes are likely to have a child with hazel eyes, but not all of the time. If one parent has hazel eyes and the other parent has green eyes, the child has a chance of inheriting green or hazel eyes.
What genes can a newborn baby inherit?
Eye color is a physical characteristic determined by the genes of both parents. As a result, the baby inherits 50% of the genetic material of the eye color of each parent. Genes are transferred to alternative forms called alleles. Each of these alleles differs from the other. There are three pairs of alleles that play in the development of eye color such as brown, green and blue.
As mentioned above, newborn eye color depends on both parent’s eye color and allele prevalence. In other cases, the baby may also develop two dominant alleles from both parents, with one or two dominant alleles. Here is a baby eye color chart to better explain this case:
- The newborn will inherit brown eyes if they receive a dominant blue allele from one parent and a dominant brown allele from the other parent.
- A newborn baby will inherit blue eyes if he inherits blue alleles from both parents. The baby is likely to receive blue eyes because the blue is recessive and not dominant.
- A baby will inherit green eyes if they receive green alleles from both parents or if they receive a green allele from one parent and a blue allele from the other.
- Babies born with blue eyes take time to produce the pigment melanin. Therefore, the baby’s eye color will not be determined until after three years.
Factors determining eye color
1. Homozygous and heterozygous
Human beings have two copies of genes. One is inherited from the other and the other is inherited from the father. Homozygous can mean that two copies match or are dominant and heterozygous can mean that two copies of genes can differ or be recessive.
2. Dominant eye color
Two of the most common eye colors are brown and green. There is a 75-95% chance that newborns will inherit brown or green eyes when both parents have the same colored eyes.
3. Recessive eye color
Blue is classified as a recessive and dominant eye color. Therefore, a newborn baby is more likely to inherit blue eyes if both parents have brown eyes.
The genotype is a combination of genes from both parents. In this case, the genotype of both parents can determine the color of the newborn’s eyes.
The phenotype refers to the physical appearance of the eye color of both parents.
Eye color chart
Carleton Coon created a color chart of the eyes using the original Martin scale. Take a look at the numbering in the eye color genetics chart below:
Pure light (16-15 on Martin’s scale)
Light blend (14-12 on Martin’s scale)
- 14: very light mixture of blue with gray or green with gray
- 13:12: Light mix of light or lightly mixed with a little mix of brown.
Mixed eyes (11-7 on the Martin scale)
- Mix of clear eyes like blue, gray and green with brown.
Dark and mixed eyes (Martin scale 6-1)
- Dark mixture: 6-5 on the Martin scale. Brown with a little mixture of light
- Dark: 4-1 on Martin’s scale. Brown, including light brown and dark brown
Rarest eye colors
|Eye colour||Cause (s)|
|Black||An abundance of melanin|
|Red / pink||Albinism and blood leakage in the iris|
|amber||A little melanin with a large amount of lipochrome|
|Green||A little melanin, a bunch of lipochrome and a Rayleigh diffusion of light|
|Purple||Lack of pigment mixed with reflected light from red blood vessels|
|Heterochromia||Increased or decreased iris pigmentation|
There isn’t one way to determine which eye color is the rarest, but there are few. Here are some of the rarer eye colors:
1. Black eyes
Black eyes are one of the rarest eye colors. Although some eye colors appear black, there are other eye colors that are dark brown, which are caused by over-availability of melanin. It can be determined by checking the eyes with bright light.
2. Red or pink eyes
There are two main conditions that cause eye color to be red or pink. Both of these conditions are caused by blood leaking into the iris and also by albinism. Although blue eyes usually form due to a lack of pigment, other forms of albinism also make the eyes appear red or pink.
3. Amber eyes
The amber eye is a solid color and includes a strong yellowish and coppery tint. This eye color is formed due to the lack of melanin and the deposit of yellow pigment called lipochrome in the iris.
4. Green eyes
The appearance of green undertones is the result of a low amount of melanin and also a phenomenon known as Rayleigh scattering. Only 2% of the world’s population has green eyes.
5. Purple eyes
Purple eyes are usually present in people with albinism. You can’t have purple eyes without the lack of albinism. An absence of pigment with the red of the light can result in purple eyes.
Heterochromia is not a fixed color but a rare eye condition where one or the other of the irises is a different color from the other. Or, there is a spot in the iris which is a different color from the rest of the iris due to the difference in pigmentation.
7. Hazel eyes
Hazel eyes are similar to brown eyes, but they are generally lighter in color. They are distinguished by a green-yellow tint. This eye color has a higher presence of melanin around the edge of the eye, resulting in a multicolored tint of copper and green, depending on the lighting. About 5-8% of the world’s population has hazel-colored eyes.
8. Silver eyes
Silver eyes are quite rare and quite similar with blue eyes. This eye color is the result of a low presence of melanin in the eye. This leads to a gray-silver appearance. Silver eyes are most common in Eastern European countries. It is one of the rare eye colors.
We hope this eye color chart article can help you determine your eye color. Let us know if this eye color guide worked.
Image source: pinterest
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