There have been several times some Nigerians or Africans with rare beautiful blue eyes have caused debates online as to why Africans who are black could have eye colour exclusively reserved for Europeans especially the Caucasians and Scandinavians.
Majority admire the eyes as they are quite unusual and beautiful while some describe them as scary and ascribe them the feature of a witch or wizard.
Recently, a Nigerian boy of Abia State descent made headlines as a result of his blue eyes and the internet saw his photos flying up and down while debates and medical interpretations were given by many internet users.
Sometime in August 2020, Risikat Moromoke Azeez and her two kids also made headlines as their photos flooded the Nigerian cyberspace because of their rare beautiful blue eyes which gave them momentary fame.
This article is handy to bring to the fore and answers the questions and speculations of many after a painstaking research why some black Africans would have such eyes.
Why a black African could have blue eyes
Having blue eyes may result from medical or circumstantial factors. In Europe, the blue eyes does not cause stirs anymore unlike it did many centuries ago.
Europe has the widest variety of eye color, and the largest proportion of people with blue eyes. Over 80 percent of the inhabitants of Estonia and Finland have blue eyes.
In contrast 90% of people living in Africa and Asia have brown eyes. In fact, brown eyes are the most commonly occurring eye color in the world.
The first thing to consider is that Europe was the epicenter of the blue-eye gene mutation because Europe was the very place the blue eye gene mutation started and spread through the world.
This might be one of the most important factors to explain the high proportion of blue eyes on the continent.
Below are the three major reasons a black African might have blue eyes.
- Past ancestors of Caucasian descent
- Genetic mutation
- Waadenburg syndrome
Past ancestors of Caucasian descent
The blue eyes could be as a result of the people having distant ancestors who are carriers of the recessive blue eye gene which might skip several generations before appearing again. This would need a detailed explanation.
Two copies of each gene is present in everyone, one from the father and one from the mother. Each gene comes in different versions called alleles.
A gene that determines eye colour can come in versions blue allele and brown allele.
It is established that most gene pigmentations of the dark colour allele is stronger or dominant while the lighter colour, in this case blue is weaker, or recessive.
One needs to inherit just one brown eye allele to have the brown colour while you will have the blue colour when you inherit two copies of the allele.
What this means is that someone with brown allele and one blue allele would have brown eyes, even though they have the DNA for blue which is hidden or recessive.
A person like this is called a carrier, because they invisibly carry the DNA for blue eyes which might manifest after many generations in an offspring.
But if two carriers for blue eyes have a child, they can have a blue eyed child! And the chances of a blue eyed child are even higher if one of the parents has that recessive trait.
So the Nigerians with blue eyes could be as a result of ancestry recessive gene as some traits are inextricably tied to ancestry. That means knowing your ancestry can reveal information about your genetics.
The likelihood of the Nigerians’ ancestors being carriers of blue eyes from Caucasian ancestry is actually quite high.
For many people, learning their ancestry may come as a shock. Learning information that calls into question your identity can feel overwhelming and disorienting.
Our genes don’t just tell us about ourselves now, but also give us a window into the past.
Genetic mutation
Genetic mutations can result from DNA copying mistakes made during cell division, exposure to ionizing radiation, exposure to chemicals called mutagens, or infection by viruses.
Germ line mutations occur in the eggs and sperm and can be passed on to offspring, while somatic mutations occur in body cells and are not passed on.
The blue eyes of Nigerians could be as a result of genetic mutation just as it happened thousands of years ago to the ancestor of the people with blue eyes world over.
Originally, humans had only brown eyes, but a genetic mutation affected the OCA2 gene in the human chromosomes resulting in the creation of a switch which literally turned off the ability to produce brown eyes.
The OCA2 gene codes for the so called P protein that is involved in the production of melanin, the pigment responsible for the colour of the human hair, eyes and skin.
The switch however does not turn off the gene entirely but limits its action on the production of melanin in the iris, effectively reducing brown eyes to blue.
The mutation of brown eyes to blue does not represent a positive nor negative mutation as it does not increase or reduce and individual’s chances of survival.
It only shows that nature constantly shuffles the human genome and creating a genetic package of human chromosomes and trying out different changes.
The odds of a new mutation causing blue eyes is very rare, especially if two siblings in the family have blue eyes. Literally a one in a million chance!
Waardenburg Syndrome
Waardenburg syndrome is a rare congenital (from birth) genetic disorder characterised by sensorineural hearing loss and abnormalities in of the hair, eyes and skin pigments, hearing loss and changes in the shape of the face.
The Waardenburg syndrome is a neurocristopathy due to gene mutations which result in abnormal neural crest differentiation during embryonic development.
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Mutations in a number of different genes can cause Waardenburg syndrome, with some differences in symptoms and signs. Expression and penetrance are also variable.
The mutations that cause Waardenburg syndrome include insertions, deletions, frameshifts, splice alterations, missense, or nonsense mutations.
This condition is named after a Dutch ophthalmologist, Petrus Johannes Waardenburg who noticed that heterochromia iridis often accompanied deafness in 1951.
The condition of Waardenburg syndrome may be inherited or new mutations can arise spontaneously and affects males and females of all races.
It has a population frequency of 1 in 40,000, and is responsible for 2–5% of all cases of congenital deafness.
Most types of Waardenburg syndrome are autosomal dominant, meaning that only one affected gene needs to be passed on to a child for them to have the syndrome.
Transmission of defects in EDN3 or EDNRB is more complex and they are usually autosomal recessive, although cases of autosomal dominant transmission with incomplete penetrance have been described.
Other mutations in some of the above genes can cause related clinical syndromes, such as Tietz syndrome (MITF gene), piebaldism (SNAI2 gene), PCWH (SOX10 gene), or ABCD syndrome (EDNRB gene).
Clinical features
Since it’s a congenital disease, the features are present from birth and the clinical signs can be subtle and this is why diagnosis may not be made until later in life.
In addition to the characteristic pigment changes and deafness, Waardenburg syndrome can be associated with musculoskeletal defects and Hirschsprung syndrome.
Doctors have identified four distinct types of the syndrome, though there may be additional subtypes.
It is common for people with this disorder to have eyes with spots or different colored eyes.
People with Waardenburg syndrome may also have an unusual facial shape and other changes in their appearance, such as prematurely gray hair.
Four major clinical types of Waardenburg syndrome are as follows:
Type 1
Type 1 Waardenburg syndrome can cause someone to have a wide space between their eyes. About 20% of people with type I experience hearing loss.
They also have patches of colour or lost colour on the hair, skin, and eyes.
Type 2
Hearing loss is more common in type 2 than type 1, with about 50 percent of people losing their hearing.
The symptoms are otherwise similar to type 1, including changes in the pigment of the hair, skin, and eyes.
This type of the disease is distinguished from type 1 primarily by an absence of a large space between the eyes.
Type 3
Type 3 is similar to types 1 and 2, frequently producing hearing loss and pigment changes.
People with this form typically have a wide space between their eyes and a broad nose.
The characteristic feature of type 3 that distinguishes it from types 1 and 2 is issues with the upper limbs.
People with type 3 may have weak arms or shoulders or malformations in their joints. Some also have intellectual disabilities or a cleft palate. Type 3 is sometimes called Klein-Waardenburg syndrome.
Type 4
Type 4 causes changes in pigmentation and may result in hearing loss. Additionally, people with this form have a disease called Hirschsprung disease.
This disorder can block the colon, causing severe constipation.
Conclusion
I believe this article will go a long way to clear the doubts and argument following the photos that go viral from time to time about black Nigerians having blue eyes.
It is obvious they are not witches or wizards and live like every other normal humans.
Some of them may have Waardenburg Syndrome but it’s rarely a life-threatening condition.
People having the condition can even leverage on the online attention given them to change their lives positively forever.
ABOUT THE AUTHOR
A Personal Development Content Creator and an author. I write about life ethics and love to document and share life hacks and experiences of people to help others make good life decisions.
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