Have you ever wondered what unites all blue-eyed people beyond their striking eye color? It turns out that this beautiful trait comes with a fascinating genetic story and some surprising characteristics.

While brown is the world’s most common eye color, blue eyes come in second. But the origin of this rare hue is far from ordinary—research suggests that every blue-eyed person can trace their lineage back to a single ancestor who lived between 6,000 and 10,000 years ago.

Yes, it’s true! Those captivating blue eyes result from a genetic mutation that “turned off” the ability to produce brown pigment in the iris.

This ancient genetic switch has its pros and cons. For instance, blue eyes are known for increased sensitivity to light. Unlike darker eyes, which contain more melanin to shield sensitive eye tissues, blue eyes lack this natural protection.