"The eyes are the window to the soul," as a timeless quote
notes. Beyond their metaphorical significance, the origins of eye color are
fascinating and even mysterious. To unravel the details of this genetic marvel,
Fox News Digital engaged in a conversation with a genetics expert on the topic.
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| Your eye color is like your fingerprint. Nobody else in the world has the exact same eye color as you do. |
Eye color specifically pertains to
the hue of your iris, the colored portion encircling the pupil. The pupil, a
small black aperture at the center, is the focus of the eye, according to
information from the Cleveland Clinic.
Comparing eye color to a fingerprint, the Cleveland Clinic emphasizes the uniqueness of each individual's eye color—no one else in the world possesses the exact same eye color as you do.
Blair Stevens, a clinical genetic
counselor and director of prenatal genetic counseling services at McGovern
Medical School, explains to Fox News Digital that eye color is contingent on
the quantity, type, and distribution of melanin, the pigment, in the iris of
the eye.
"Melanin production is determined by someone’s genetic information,
which we inherit from our parents," Stevens highlights. Eye color is
classified as a "polygenic" trait, denoting the involvement of
multiple genes.
Certain genetic variants prompt
increased melanin production, resulting in darker eye colors, while others lead
to reduced melanin production, yielding lighter eye colors, according to
Stevens. Additionally, melanin production continues to evolve after birth,
which explains why newborns' eye color may undergo changes as they develop.
Blair Stevens clarifies that "recessive" traits typically manifest only if someone inherits the recessive gene from both parents. In contrast, a "dominant" trait inherited from just one parent can conceal a recessive trait from the other parent.
Using the analogy of mixing paint,
Stevens notes that brown eye color is considered dominant to blue, akin to the
result when brown is mixed with blue paint, creating a color that appears more
brown than blue.
Addressing the scenario where one
parent has brown eyes and the other has green, leading to a child with blue
eyes, Stevens emphasizes that individuals inherit two copies of each gene, one
from each parent, and multiple genes contribute to determining eye color. She
likens this to a watercolor palette with options for blue, green, and brown
paint.
Regarding the dominance of genes in
traits like eye color, hair color, and skin color, Stevens explains that these
features are all influenced by melanin, the pigment our bodies produce. Our
genes play a crucial role in dictating the type, structure, and amount of
melanin produced.
Blair Stevens explains that individuals with genes producing high amounts of melanin are more likely to have darker eye color, hair color, and skin color compared to those with genes generating lower amounts of melanin. However, some genes influencing hair color may not impact eye color, and vice versa.
Siblings can indeed have different
eye colors, depending on the combination of genes inherited by each sibling,
according to Stevens.
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| Only about 1 in 4 people in the U.S. have blue eyes, per the Cleveland Clinic |
As for the most common eye color,
brown holds that distinction globally, with approximately half of the U.S.
population having brown eyes. Blue or gray eyes are found in around 1 in 4
people in the U.S., while green eyes are the least common, occurring in only 9%
of the population. Hazel eyes, a combination of brown and green, are present in
about 18% of people in the United States.
Stevens acknowledges the complexity
of the inheritance pattern for determining eye color and notes that there is
still much to be learned about the genetics of eye color. Additionally, she
highlights that eye color cannot be reliably predicted through genetic testing.
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