Microevolutionary Defenses against Kuru

Via Twitter: Razib at ScienceBlogs reports on cannibals, kuru, and microevolution.

127V is extremely efficacious against fatality due to kuru. Looking through the pedigrees in a region of very high kuru exposure the researchers found that of the individuals who carried 127V, only 1 out of 36 in the parent generation died of kuru. By contrast, 33 of 218 parents from those carrying 127G only (the modal allele) had died of kuru (some of these presumably would also have carried the protective variant of 129). When the researchers looked at the 127V haplotype, the nature of the variation around this mutation implied that a common ancestor existed ~10 generations ago, with a 95% confidence interval 7 to 15 generations. That means that all of the copies of 127V extant today in the Fore descend from one particular copy present on the order of 250 years in the past within the population.