Intelligence & genetics

A news-item on GenomeWeb:

Rather than having genetic variants that make them smart, brainy people may lack mutations that make them less clever, New Scientist reports.

In a paper posted to BioRxiv, researchers from the University of Edinburgh report that they genotyped some 20,000 people from the Generation Scotland family cohort to tease out the effects of gene variants on intelligence, extraversion, and neuroticism. As the cohort includes family members, the researchers could delve into variants not typically found in genome-wide association studies of unrelated people.

.....

In particular, New Scientist says that CNVs, structural variants, and rare variants seem to affect intelligence. As rare variants are more likely to be harmful, New Scientist says it appears that a person's intelligence might be in part due to their mutational load.

Note 1: CNV = copy number variations
Note 2: It would seem high intelligence is the norm, and variation away from the norm reduces intelligence.  Rather amusing, and this would be a blow to the IQ-metricians, I think.