Wikimedia Commons: A genetic mutant.
If you've got blue eyes, shake the hand of the nearest person who shares your azure irises: He or she may be a distant cousin.
Danish researchers have concluded that all blue-eyed people share a common ancestor, presumably someone who lived 6,000 to 10,000 years ago.
"Originally, we all had brown eyes," Professor Hans Eiberg of the University of Copenhagen said in a press release. "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."