Blue eyes are caused by a gene mutation. For years, researchers had searched for it on the OCA2 gene. The OCA2 gene determines how much brown pigment is in our eyes. But what they were looking for ...

The island is home to 100 individuals with blue eyes, another 100 with brown eyes, and a Guru sporting green eyes. The puzzle further complicates things by stating: "So any given blue-eyed person ...