DNA behind half variation in human intelligence

GENETIC differences between people could account for up to half the variation in individual intelligence, according to a new study.

Researchers at the University of Edinburgh studied two types of intelligence in more than 3,500 people from Edinburgh, Aberdeen, Newcastle and Manchester.

The team found that 40 per cent of the variation in knowledge and 51 per cent of the variation in problem-solving skills between individuals could be explained by DNA differences.

The study, published in the journal Molecular Psychiatry, examined more than half a million genetic markers on each person and is the first to find a genetic contribution by testing people's DNA for variations.

Professor Ian Deary, one of the research leaders, said: "The findings leave a lot of room for environmental influences and for interactions between people's genes and their environments. It's a start to understanding the observed relationship between people's thinking skills and outcomes in life, and to understanding why some people cognitively age better than others.

"Our broader aim is to provide information that can help people preserve these skills as long as possible through the life-course."