Imperial College London has found that two networks of genes determine whether people are intelligent or not so bright.
Genes which make people intelligent have been discovered and scientists believe they could be manipulated to boost brain power.
Researchers have believed for some time that intellect is inherited with studies suggesting that up to 75 per cent of IQ is genetic, and the rest down to environmental factors such as schooling and friendship groups.
But until now, nobody has been able to pin-point exactly which genes are responsible for better memory, attention, processing speed or reasoning skills.
Now Imperial College London has found that two networks of genes determine whether people are intelligent or not-so-bright.