NOW I see the previous posting to rmr
Found something interesting:
Eiberg and his team examined the DNA of blue-eyed individuals in countries including Jordan, Denmark, and Turkey. This genetic material came from females, so it traced maternal lineages. What they were able to show is that all the people who have blue eyes have exactly the same gene changes that are linked to the one mutation that makes eyes blue.
In other words, this new research has determined that people with blue eyes have a single, common ancestor. "They have all inherited the same switch at exactly the same spot in their DNA," says Eiberg. That genetic switch somehow spread first throughout Europe and now other parts of the world, presumably because it gave the holder some sort of evolutionary advantage.