Now Imperial College London has found that two networks of genes determine whether people are intelligent or not-so-bright.

 

They liken the gene network to a football team. When all the players are in the right positions, the brain appears to function optimally, leading to clarity of thought and what we think of as quickness or cleverness.

 

However when the genes are mutated or in the wrong order, it can lead to dullness of thinking, or even serious cognitive impairments.

 

Scientists believe that there must be a 'master switch' regulating the networks and if they could find it, they could 'switch on' intelligence for everyone.

"We know that genetics plays a major role in intelligence but until now haven't known which genes are relevant," said Dr Michael Johnson, lead author of the study from the Department of Medicine at Imperial College.

 

"This research highlights some of genes involved in human intelligence, and how they interact with each other.

 

"What's exciting about this is that the genes we have found are likely to share a common regulation, which means that potentially we can manipulate a whole set of genes whose activity is linked to human intelligence.

 

"Our research suggests that it might be possible to work with these genes to modify intelligence, but that is only a theoretical possibility at the moment - we have just taken a first step along that road."

 

Genetic testing is already used

on a disease by disease basis within the NHS.

Photo: Alamy

 

 

In the study, published in the journal Nature Neuroscience, the team of researchers looked at samples of human brain from patients who had undergone neurosurgery for epilepsy.

 

They analyzed thousands of genes expressed in the human brain, and then combined the results with genetic information from healthy people who had undergone IQ tests and from people with neurological disorders such as autism spectrum disorder and intellectual disability.

 

They conducted various computational analyses and comparisons in order to identify the gene networks influencing healthy human cognitive abilities.

 

Remarkably, they found that some of the same genes that influence human intelligence in healthy people were also the same genes that cause impaired cognitive ability and epilepsy when mutated, networks which they called M1 and M3.

 

Dr. Michael Johnson added:

"Traits such intelligence are governed by large groups of genes working together - like a football team made up of players in different positions.

 

"We used computer analysis to identify the genes in the human brain that work together to influence our cognitive ability to make new memories or sensible decisions when faced with lots of complex information.

 

"We found that some of these genes overlap with those that cause severe childhood onset epilepsy or intellectual disability.

 

"This study shows how we can use large genomic datasets to uncover new pathways for human brain function in both health and disease. Eventually, we hope that this sort of analysis will provide new insights into better treatments for neuro-developmental diseases such as epilepsy, and ameliorate or treat the cognitive impairments associated with these devastating diseases."

Earlier this year a team at King's College London discovered that up to 65 per cent of the difference in pupil's GCSE grades was down to genetics, after analyzing genetic data from 12,500 twins.

 

They found that all exam results were highly heritable, demonstrating that genes explain a larger proportion of the differences between children, between 54 and 65 per cent.

 

 

Grey matter was thought

to be behind intelligence.

 

 

Previously it was thought that intelligence was determined by the formation of the cerebral cortex, the outermost layer of the human brain, also known as 'grey matter.'

 

Grey matter plays a key role in memory, attention, perceptual awareness, thought and language.

 

In contrast shared environmental factors such as home and school environment contributed between 14 and 21 per cent. The rest was made up by individual external influences such as diseases or friends.

 

Report author Professor Robert Plomin believes that children should be genetically screened at the age of four so that an individualized curriculum could be tailored to their needs.

"Understanding the specific genetic and environmental factors influencing individual differences in educational achievement - and the complex interplay between them - could help educationalists develop effective personalized learning programs, to help every child reach their potential by the end of compulsory education," he said.

However other genetics experts have warned that even having intelligence gene networks does not guarantee success.

 

Darren Griffin, Professor of Genetics at the University of Kent, said:

"Genetics is the science of inheritance, not pre-determinism, and there is no substitute for hard work and application."