If you're interested in athletic performance and genetics, read Daniel Macarthur on ACTN3, sprinting, and Jamaica:
At this point I probably should confess to having a more than casual interest in this story: I was one of the authors on the first study showing an association between this gene and elite athlete status back in 2003, and this gene has been the central focus of my research for a good part of the last six years.
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It is almost certainly true that Usain Bolt carries at least one of the "sprint" variants of the ACTN3 gene, but then so do I (along with around five billion other humans worldwide). Indeed, I'm fortunate enough to be lugging around two "sprint" copies - but that doesn't mean you'll see me in the 100 metre final in London in 2012.
