“There is “a highly significant association” between the CHRM2 gene and intelligence according to a 2006 Dutch family study. The study concluded that there was an association between the CHRM2 gene on chromosome 7 and Performance IQ, as measured by the Wechsler Adult Intelligence Scale-Revised. The Dutch family study used a sample of 667 individuals from 304 families.[59] A similar association was found independently in the Minnesota Twin and Family Study (Comings et al. 2003) and by the Department of Psychiatry at the Washington University.[60]”
Here’s an example of the kind of thing I mean:
“There is “a highly significant association” between the CHRM2 gene and intelligence according to a 2006 Dutch family study. The study concluded that there was an association between the CHRM2 gene on chromosome 7 and Performance IQ, as measured by the Wechsler Adult Intelligence Scale-Revised. The Dutch family study used a sample of 667 individuals from 304 families.[59] A similar association was found independently in the Minnesota Twin and Family Study (Comings et al. 2003) and by the Department of Psychiatry at the Washington University.[60]”
http://en.wikipedia.org/wiki/Intelligence_quotient
So: “We are not finding any IQ genes” seems to be rather inaccurate.
I note that there has been at least one negative finding for the same gene:
“No Association Between Cholinergic Muscarinic Receptor 2 (CHRM2) Genetic Variation and Cognitive Abilities in Three Independent Samples.”
http://www.medicine.manchester.ac.uk/research/PubDetails/index.aspx?ID=37741
The study appears to be looking at SNPs—though it tracks quite a number of them. Possibly the relevant variation has a geographic component.