EDINBURGH, Scotland, Aug. 9 (UPI) -- A study offers the first direct biological evidence that genes and inheritance have a big role in intelligence, a Scottish researcher says.
Researcher Ian Deary of the Center for Cognitive Aging at the University of Edinburgh says previous family and twin studies strongly suggested many characteristics of intelligence are inherited, but no specific genes or gene variants had been linked with such traits.
In the latest study, investigators found many different gene variants with small individual effects are cumulatively involved in human intelligence, WebMD.com reported Tuesday.
Deary and colleagues in Europe and Australia tested the DNA of 3,500 people for genetic variations that were then correlated with the participants' performance on tests designed to assess two standard measures of intelligence -- knowledge and problem solving.
The findings show between 40 percent and 50 percent of the differences in scores among the study participants resulted from specific genetic differences.
"The findings leave a lot of room for environmental influences and for interactions between people's genes and their environment," Deary says. "It is a start to understanding the relationship between people's thinking skills and outcomes in life and to understanding why some people cognitively age better than others."
