Here's a paper - soon to appear in Psychological Science - which says that Most Reported Genetic Associations with General Intelligence Are Probably False Positives
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 ...
