Excellent letter the other day in the Guardian:

Genetic diversity within human populations decreases as distance from Africa increases. This is good evidence that humans arose in a small region and later dispersed (Africa cradle of humankind, study shows, July 19). This argument could be applied to biblical fundamentalism. There are people who take the story of Noah’s ark literally. If it really did happen, every species of animal should show a similar kind of distribution around Mount Ararat. This doesn’t happen. So, biblical fundamentalism only makes one testable prediction, and it’s wrong.
John L Morton
University of Glamorgan

(There’s a summary of a 2005 paper about the genetic diversity point, though it’s been more strongly made lately.)

I love that letter – so short, neat, not a word wasted. From science, to biblical fundamentalism to case dismissed in a few sentences. Now that’s science for ya.

Alternatively, you could read the hundreds of pages in Dawkins’s book, but I think I prefer this letter.