Hazel eyes are an interesting eye color that combines shades of brown and green. They can appear to shift in color depending on lighting conditions. Many people consider them to be quite unique and beautiful. But just how rare are hazel eyes? Let’s take a closer look at some statistics on the prevalence of this eye color.
Definition of Hazel Eyes
Hazel eyes contain a combination of melanin pigments – eumelanin (brown) and pheomelanin (amber/green) in the iris. This results in an eye color that has both brown and greenish tones that can shift or vary. Generally, hazel eyes will appear brown around the pupil and green on the outer edge of the iris. However, there are many variations in hazel eye color.
Some key defining features of hazel eyes:
– Multicolored – Contains shades of brown, green, gold and orange
– Appear to shift in color – Can look more green or brown depending on lighting
– Distinct pattern – Brown around the pupil fading to green on the edge
– May contain yellow/gold flecks
Hazel eyes are sometimes confused with amber and light brown eyes. But true hazel eyes will have an obvious blend of brown and green.
Prevalence of Hazel Eyes Worldwide
Hazel eyes are relatively uncommon globally. Exact statistics vary, but they are estimated to occur in:
– 5-10% of people worldwide
– Around 5% of the global population
– 5-8% of Western populations
This makes them substantially rarer than brown eyes (most common globally at 70-90% prevalence) and blue eyes (second most common at around 8-10% prevalence).
Here is a breakdown of the estimated prevalence of hazel eyes in populations across different world regions:
| Region | Prevalence of Hazel Eyes |
|---|---|
| Europe | 5-10% |
| United States | 5-8% |
| South America | 3-5% |
| Asia | 1-3% |
| Africa | 1-2% |
As shown, hazel eyes are most common in European and North American populations. They are substantially rarer among Asian, African and South American ethnicities.
Prevalence of Hazel Eyes by Country
There is some variation in hazel eye prevalence across different countries and ethnic backgrounds:
– **England:** Up to 10% prevalence. Hazel eyes are relatively common.
– **Spain:** Approximately 9% prevalence. Also fairly common.
– **United States:** 5-8% of the population. More common among Caucasians.
– **Brazil:** Around 3-4% prevalence overall. Higher rate among white Brazilians.
– **China:** Less than 1% of Chinese people have hazel eyes. Very rare.
– **Nigeria:** Virtually non-existent. Brown eyes are near universal.
– **India:** Extremely rare at less than 0.5% prevalence. Brown eyes dominate.
So in summary, hazel eyes are most common in England, other parts of Britain, Spain and among white Americans. They become progressively rarer in South America, very rare in Asia and nearly non-existent in Africa.
Changes in Prevalence Over Time
It is thought that hazel eyes first arose as a rare mutation in some European populations, as far back as 10,000-15,000 years ago. Some key points about changes over time:
– They have always been relatively uncommon.
– Likely increased slightly in prevalence across Europe over thousands of years but remained a minority.
– Were carried over to the Americas and became more common among some white settler populations.
– Have probably decreased slightly in prevalence in recent decades due to increased racial integration.
Overall, hazel eyes have likely hovered around 5-10% prevalence in Europe and white populations over time. They have consistently remained quite rare among non-European groups.
Cause of Hazel Eyes
The cause of hazel eye color is the same as other eye colors – the amount and type of melanin pigment in the iris. Key points:
– Brown eyes have a lot of melanin concentrated around the pupil.
– Blue eyes have very little melanin concentrated on the outer part of the iris.
– Green eyes have low to moderate melanin distributed evenly.
– Hazel eyes have moderate melanin concentrated around the pupil that fades out to low levels at the edge.
This specific distribution of melanin levels gives hazel eyes their multicolored appearance. Genetically they are similar to green eyes and require some of the same gene variants.
Genetics and Inheritance
Hazel eye color is influenced by multiple genes that control melanin production and distribution. Some key genetic factors:
– **HERC2 gene** – Reduces overall melanin production. Important for lighter eye colors.
– **OCA2 gene** – Associated with green/hazel eyes. Helps determine melanin content.
– **SLC24A4 gene** – Involved in calcium transport in melanocytes. Linked to green/hazel eyes.
– **IRF4 gene** – Regulates OCA2. Variants associated with hazel eyes.
– Interactions between these and many other genes ultimately help determine hazel eye color.
In terms of inheritance:
– Hazel is a recessive trait like green eyes. Brown dominance means both parents must carry the trait to have a hazel-eyed child.
– If one parent has hazel eyes and the other has brown eyes, their children are more likely to have brown eyes.
– Two hazel-eyed parents are much more likely to have hazel-eyed children.
– The exact eye color spectrum in hazel-eyed offspring can be quite variable.
Notable People with Hazel Eyes
Many celebrities and famous figures have hazel eyes. Some examples include:
– Taylor Swift
– Eddie Redmayne
– Angelina Jolie
– Harrison Ford
– Prince Harry
– Madonna
– Robert Downey Jr.
– Marilyn Monroe
– Elvis Presley
– Paul Newman
So hazel eyes certainly occur in popular and famous people. But it is still a relatively uncommon eye color in the general population.
Conclusion
In summary, hazel eyes are quite rare globally, occurring in only around 5-10% of people worldwide. They are most prevalent in European populations and people of European descent, especially in Britain. Hazel eyes arise from a specific distribution of melanin pigments in the iris. They are determined by a complex interaction of genetic factors. While hazel eyes are considered quite attractive, their rarity means they will probably continue to only occur in a small fraction of the global population.
