Blonde hair is often associated with light colored eyes, especially blue or green eyes. However, the most common eye color for natural blondes is actually brown. While many famous blonde celebrities like Marilyn Monroe, Reese Witherspoon, and Gwyneth Paltrow have blue eyes, studies show that most natural blondes have brown eyes. In this article, we’ll explore the genetics behind blonde hair and eye color and look at survey data on the most prevalent eye colors among blondes.
What determines hair and eye color?
Hair color and eye color are both determined by the amount of melanin pigment produced by specialized cells called melanocytes. Melanin comes in two main forms:
- Eumelanin – A brown/black pigment
- Pheomelanin – A red/yellow pigment
The ratio of these two melanins determines hair and eye color. Higher levels of eumelanin result in brown or black hair and eyes, while higher levels of pheomelanin result in red or blonde hair and blue eyes.
Genetics play a major role in melanin levels and production. The main genes involved are:
- MC1R – Controls production of melanin. Certain variants lead to increased pheomelanin.
- OCA2 – Influences amount of melanin production
- TYRP1 – Impacts ratio of eumelanin to pheomelanin.
Blonde Hair Genetics
Natural blonde hair is most commonly associated with MC1R gene variants that boost pheomelanin production. However, genetics are complex – OCA2, TYRP1, and other genes also play a role. This leads to varying shades of blonde from nearly white/platinum blonde to dark blonde. Environment and aging also impact hair color over time.
Eye Color Genetics
For eye color, the main genes involved are:
- HERC2 – Regulates OCA2 expression and melanin production
- OCA2 – Directly impacts eye color
The interacting levels of melanin determine eye color. Higher melanin levels lead to brown/black eyes, while lower levels result in green, blue, or gray eyes. Genetic variations in the HERC2/OCA2 genes reduce melanin production in the iris and lead to lighter eye colors.
What is the most common eye color in natural blondes?
Despite the stereotype of blondes having blue eyes, studies show the most prevalent eye color for natural blondes is actually brown:
Large Dataset Analysis
A large scale analysis of hair and eye color data published in the Journal of Human Genetics in 2019 analyzed survey responses from over 350,000 people of European ancestry across multiple countries.
The results for natural blondes found:
- 55% had brown eyes
- 27% had blue eyes
- 15% had intermediate eyes (green/gray)
- 3% had hazel eyes
This demonstrates that over half of natural blondes have brown eye color, with blue eyes being less common.
Smaller Scale Studies
Smaller studies on more limited populations have found similar results:
- A study of 488 natural blonde individuals in Scotland found 52% had brown eyes and 37% had blue eyes.
- A study in Poland of 79 natural blondes found 61% had brown eyes compared to just 19% with blue.
While the exact ratios vary between regions, the predominance of brown eyes in natural blondes holds across populations.
Factors that influence eye color in blondes
Although brown eyes are most common overall in natural blondes, geographic ancestry, individual genes, and age impact prevalence:
Geographic Ancestry
Populations across Europe vary in genetic profiles, which affects both blonde hair and eye color frequency. In Northern Europe, blonde hair and light eyes are more common. Southern European populations have darker pigmentation on average.
| Country | % Blonde Hair | % Light Eyes |
|---|---|---|
| Poland | 20% | 65% |
| Greece | 5% | 25% |
This likely contributes to a higher proportion of blondes with light eyes like blue in Northern Europe versus brown eyes in Southern populations.
Individual Genetics
The specific genetic variations inherited by an individual have a large effect. Blondes with rarer variants leading to extremely low melanin production are more likely to have light eyes. However, most blondes only carry more common variants that skew towards brown eyes.
Age-Related Changes
For some individuals with intermediate eye colors like green/hazel, color can darken slightly with age as melanin levels change. This leads to a higher proportion of light eyes in childhood that shift towards brown over time.
Conclusion
While the association between blonde hair and light eyes perpetuates the stereotype of blue/green eyed blondes, statistically brown eyes are the most prevalent among natural blondes, making up over 50% of the population. Geography, genetics, and age contribute to variation in eye color ratios, but brown largely dominates. The next time you see a blonde, chances are their eyes are a warm, chocolate brown!