Researchers at England's Institute of Psychiatry obtained intelligence scores for 7000 seven-year-olds based on verbal and non-verbal reasoning tests. They then took DNA samples from the children in the hope of identifying genetic differences between the high and low scorers, and identified genetic variants that appear to be play some role in differences in intelligence.They found that the individual effects of the six genes accounted for just one percent of the variation in intelligence between individuals. This implies that intelligence results from the cumulative effect of a wide combination of genes, rather than individual ones, not to mention other non-genetic factors.
Hmm. I thought we sort of knew that.
The AFP report here.