"But we're not still evolving..."

A genetic mutation that protects humans from kuru - a disease passed on by eating infected brains - has been identified, and crucially, it is only two hundred years old.

Simon Mead, of the University College London's prion research centre, and colleagues examined DNA from the brains of Fore people from Papua New Guinea, where the ritual practice of eating human brains persisted until the 1950s. They compared those who had eaten brains and died to those who had done so and survived, and found in the latter group a hitherto gene variant which protects the bodies in which it resides from kuru. The researchers claim that it arose only two hundred years ago and therefore that it demonstrates modern natural selection in action.

This kind of research is an excellent rebuttal to creationist/anti-science rhetoricians, or simply an answer to innocent lay inquirers, who question the ability of genetic mutations to produce phenotypic effects beneficial to survival. The answer is simply that it does happen, even if less commonly than mutations that damage the body.

Kuru is a horrendous disease that turns brain tissue into non-functioning, spongy mush, much like BSE in cows and vCJD in humans, so not only is the research a fascinating reminder of the effect of natural selection on humans, but also hopefully a step forward in preventative understanding.

http://www.newscientist.com/article/dn18172-gene-change-in-cannibals-reveals-evolution-in-action.html

Mead, S. et al (2009) 'A novel protective prion protein variant that colocalizes with kuru exposure' New England Journal of Medicine, 2009, volume 351 p. 2056