Sci is at Neurotic Physiology today, talking about a recent study looking at a single nucleotide polymorphism in the mu-opioid receptor. It's a simple, single mutation, that has some pretty big effects, especially in pain sensitivity. Though it does make me wonder, why does every picture of back pain have a shirtless person with a glowing back? I guess you can't have back pain with your shirt on. Head over and check it out.