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.
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.