Everyone had brown eyes. Then, at some point, there was a mutation that turned off that particular gene. The result was that the body's ability to produce the right kind of protein for the eye was limited, changing the color from the dominant brown to a more muted blue. If two parents both pass down this mutation, their kid has blue eyes, but if one parent passes down the original gene, allowing the protein to be made, then the kid's eyes are brown. Hence, blue eyes are a recessive trait. I'm unclear about where other eye colors like green and hazel come in, but they may have to due with varying amounts of protein being made. I digress. The point is that one small mutation in one person a long time ago caused all the blue eyes we see today and everyone with blue eyes is in fact related to that one person. Pretty cool, right?














