So after my wingeing about the quality of genetic associations found through candidate gene studies, it’s only appropriate that I point to a fun candidate gene association study published this week in Nature.
The interesting point here is that the organism isn’t humans, but rather baboons, and the phenotype is susceptibility to malaria. Briefly, the authors find that a SNP in the promoter of the Duffy locus (recall that a mutation that abolishes the expression of Duffy in humans leads to protection from Plasmodium vivax and is one of the best characterized instances of recent positive selection in our species) appears to lead to protection from a malaria-like disease in baboons. The authors seem to really, really want this polymorphism to also be under selection in baboons (to complete the parallel story to humans), but they can’t bring themselves to say the evidence is anything more that “suggestive” (and to be honest, even that may be wishful thinking).
So is the association true? The study suffers from the same problem of candidate gene studies mentioned before, in that it’s small and the evidence for an association is fairly weak. If I had to bet, I’d guess no, the association isn’t real. But collecting and genotyping a large sample of baboons is simply not feasible at this point (if it ever will be), so this is what’s possible, and it’s a kind of fun, suggestive study that would be really cool if it ends up being true.