A team of scientists traced blue eyes to a single genetic mutation that occurred between 6,000-10,000 years ago in the OCA2 gene, which determines eye, hair, and skin color; this mutation reduced the production of brown melanin in the eyes, leading them to appear blue rather than brown as originally seen in all humans; now all blue-eyed individuals can trace the same gene change back to this single ancient mutation.

1. Genetic mutation
makes brown eyes blue
A team of scientists has tracked down a
genetic mutation that leads to blue eyes

2. People with blue eyes
have a single, common ancestor,
• A team of scientists has tracked down
a genetic mutation that leads to blue eyes
• Mutation occurred between 6,000 and 10,000
years ago
• Before then, there were no blue eyes

3. Originally, we all had brown eyes.
• Mutation affected the OCA2 gene, the pigment
that gives color to our hair, eyes and skin
• Mutation “turned down” the power to produce
brown eyes
• If the OCA2 gene had been completely shut
down, our hair, eyes and skin would be melanin-
less, a condition known as albinism

4. Baby blues
• All have exactly the same gene changes that are
all linked to this one mutation that makes eyes
blue
• Blue-eyed individuals only have a small degree
of variation in the amount of melanin in their
eyes

5. Sources
• http://www.msnbc.msn.com/id/22934464/