(This isn't my regular journal but a good article that I wanted to share, so I hope I'm not stepping on anyone's toes!)
The genes coding for lactose tolerance in Europeans is well known. However, there are populations in Africa that are also able to produce lactase beyond weaning but the genes coding for this have not been explored. Tishkoff and colleagues identify the SNPs associated with lactase persistence in these African populations, and find that it is different from those that code for lactase persistence in Europeans. This represents convergent evolution (and an adaptation) in humans as the result of strong selective pressure after the domestication of mammals.