About eight to ten percent of the global population boasts striking blue eyes, and there's a fascinating genetic story behind this unique trait.
Blue eyes, the second most common eye color worldwide, are believed to have originated approximately 6,000 to 10,000 years ago. Originally, all humans had brown eyes, albeit in varying shades. However, the wide prevalence of blue irises stems from a genetic mutation, pinpointed to a gene known as HERC2.
HERC2 plays a crucial role in eye color determination by suppressing OCA2, which is responsible for the range of brown eye shades.
Professor Hans Eiberg, of the Department of Cellular and Molecular Medicine at a university, explains that "originally, we all had brown eyes. But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a 'switch', which literally 'turned off' the ability to produce brown eyes."
This genetic shift is believed to have started when humans migrated from Africa to Europe, marking the genesis of blue eyes. Intriguingly, research indicates that all individuals with blue eyes share a common ancestor.
While the identity of the first blue-eyed individual remains a mystery, the shared genetic mutation among all blue-eyed people offers compelling evidence of their common heritage.
According to Professor Eiberg, this research highlights how nature constantly reshuffles the human genome, resulting in a diverse genetic mix of human chromosomes and various genetic alterations.
Yet, the story of blue eyes doesn't end here.
Blue-eyed individuals also exhibit increased sensitivity to light.
The amount of melanin in the iris, the colored part of the eye, serves as a natural defense against UV radiation and the harm caused by blue light, according to Auckland Eye.
Consequently, those with blue eyes, who generally possess lower melanin levels, are more prone to experiencing photophobia, which denotes heightened sensitivity to light.
However, having blue eyes comes with its own set of advantages.
A study led by Professor Joanna Rowe from the University of Louisville suggests that individuals with blue eyes tend to excel in strategic thinking. While this observation lacks a definitive scientific explanation, it remains a compelling insight.
"It is just observed, rather than explained. There's no scientific answer yet," the professor clarifies.
Numerous prominent figures with blue eyes have demonstrated exceptional intelligence, including Stephen Hawking, Alexander Fleming, and Marie Curie. The connection between eye color and intellect continues to intrigue researchers.