Intelligence IS in the genes, say brain experts

BYLINE: Paul Kendall

SCIENTISTS have published groundbreaking images of the brain which prove that intelligence depends heavily on the genes.

The images show that the volume of grey matter in the frontal parts of the brain which relates to a person's IQ score is determined by the genetic makeup of an individual's parents. The discovery is likely to reignite the nature versus nurture argument in which some scientists claim a child's environment contributes relatively little to intelligence.

And it could bolster attempts to develop ways of genetically engineering a child's IQ.

Researchers from the University of California at Los Angeles, led by Dr Paul Thompson, compared 20 pairs of twins, half of whom were identical and half non-identical.

Identical twins have the same genes, whereas non-identical twins, like ordinary siblings, share about half. Features which are the same in identical twins, but not in nonidentical, are therefore likely to be governed by genetic factors.

New 3D imaging techniques enabled the scientists to look for subtle similarities and differences in brain structure. Dr Thompson said: 'We were stunned to see that the amount of grey matter in frontal brain regions was strongly inherited and also predicted an individual's IQ score.' Previous studies have suggested that a number of cognitive skills are surprisingly inheritable, including IQ, verbal and spatial abilities, perceptual speed, and even some personality traits.

But Dr Thompson's images are the first to uncover how genetic differences influence brain structure and intelligence.

The researchers, writing in Nature Neuroscience, said: 'We found that brain structure is under significant genetic control.

'The quantity of frontal grey matter, in particular, was most similar in individuals who were genetically alike. Intriguingly, individual differences were tightly linked with individual differences in IQ.'

p.kendall@dailymail.co.uk

LOAD-DATE: November 6, 2001