Scientists once thought there were fewer than half a dozen "intelligence genes," but researchers are discovering there are a lot more than that.
A study released today concludes that many genes -- perhaps 1,000 or more -- play a role in intelligence. As with height, it's the overall effect of all these genes that accounts for differences in people's intelligence.
That's kept scientists from being able to identify which specific genes are involved.
The findings add to evidence that even the most powerful genes only have a weak influence on overall intelligence.
Researchers say understanding the genetics of intelligence may
eventually help them get a better handle on mind-robbing diseases
such as Alzheimer's.