Monday, February 16, 2009

Blue eyes

"Take blue eyes. Darwin, like many Europeans, had blue eyes. In early 2008, Hans Eiberg and his colleagues at the University of Copenhagen announced that they had found the genetic mutation common to all pure blue-eyed people. The mutation is a single letter change, from A to G, on the long arm of chromosome 15, which dampens the expression of a gene called OCA2, involved in the manufacture of the pigment that darkens the eyes. By comparing the DNA of Danes with that of people from Turkey and Jordan, Eiberg calculated that this mutation happened only about 6,000-10,000 years ago, well after the invention of agriculture, in a particular individual somewhere around the Black Sea. So Darwin may have gotten his blue eyes because of a single misspelled letter in the DNA in the baby of a Neolithic farmer."

Matt Ridley, Darwins Legacy, National Geographic

Six thousand years is the blink of an eye in evolutionary terms.