The authors tried to replicate published associations between particular genetic variants (SNPs) and IQ (specifically the g factor). They looked at three datasets, a total of about 10,000 people, and didn’t confirm any of the 12 associations.
As Razib Khan says in his post on this, “My hunch is that these results will be unsatisfying to many people.” I’d go further and say that no-one will be happy with these.
For those who believe that IQ is purely environmental and not genetic, any satisfaction they might feel will be short lived because these authors did replicate the recent finding that genetic variants explain about 50% of the variance in IQ. Looking at all SNPs together, there was a strong correlation between “genetic similarity” and similarity in IQ. That independently confirms what the much-criticized twin studies of IQ said – IQ is about 50% heritable.
But for people who do believe in the genetics of intelligence, this shows us that we have no idea what the genes are, and that everything published so far has been pretty much for naught.
This is consistent with prior studies that have tried to replicate gene-IQ associations. It just doesn’t happen. They turn out to be statistical artifacts, a common problem encountered when doing the number of tests involved in genome association studies.
As for the strong correlation between genetic similarity and similarity in IQ? I’m not remotely disappointed in the finding. It’s exactly what we would expect if those who were genetically similar shared a large portion of their environment as well. They do, in fact, both because families and immigrant groups tend to cluster in similar environments and because a number of things more directly encoded in genes (illness, skin color, etc.) have an effect on the environment in which intelligence is developed.
I’m only disappointed in those who think that this is somehow conclusive evidence of subtle genetic effects on IQ.