The story about HERC2 & OCA2 is getting a lot of press; that is, the genetics behind how people have blue eyes. But see this in ScienceNow:
There are still large questions, though. Why did blue eyes persist? Scientists say it is difficult to see how eye color would have an environmental advantage, as skin color does. Some theories suggest that women may have played a role in driving the selection. Perhaps, Kayser says, "the females thought it more exciting to have a male with blue eyes."
I already posted this before: the SNPs which are used to predict blue eyes also track skin color variation. In other words, pleiotropy. This shouldn't be a surprise, OCA2 is a pigmentation locus which in many cases doesn't exhibit tissue specific expression patterns; its name derives from the fact that some forms of albinism are associated with mutants on it. In any case, ...
