It doesn't matter how much you study, HALF of your intelligence is down to your genes, scientists claim

• Genes account for more than half the differences in intelligence between people
• As well as genes, environmental factors such as parenting and nutrition are key 
• The new findings will fuel the 'nature versus nurture' debate over cleverness

Genes we are born with account for more than half the differences in intelligence between people, a study has shown.

The new findings will fuel the 'nature versus nurture' debate over what makes us clever or dumb.

As well as genes, environmental factors such as parenting, nutrition and exposure to chemicals in the womb are also thought to have a significant effect.

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Genes we are born with account for more than half the differences in intelligence between people, a study has shown. The new findings will fuel the 'nature versus nurture' debate over what makes us clever or dumb (stock image) 

DO WE HAVE 'INTELLIGENCE GENES'?

Scientists know about 52 genes linked to the intelligence trait, 40 of which are relatively new discoveries.

An international research team led by Vrije Universiteit Amsterdam last year studied genetic data from over 78,000 individuals.

The data included information on DNA genotypes and intelligence scores, which led the team to discover new genes and biological routes for intelligence.

Scientists found that many people with these genes are more likely to have other traits, including being tall, thin and unlikely to smoke.

People who expressed the genes were less likely to suffer from Alzheimer's disease, depressive symptoms, schizophrenia and obesity.

In a more recent study, researchers have found genes we are born with account for more than half the differences in intelligence between people. The new study, from the University of Edinburgh, highlights the contribution of rare genetic variants which appear to have a disproportionate impact on intelligence.

Scientists examined thousands of genetic markers in the DNA of 20,000 people looking for signals associated with IQ.

They found that the combined effect of rare and common genetic variants explained at least half of the difference in intelligence between individuals.

This matched estimates from earlier twin and family studies that had been suspected to be overestimates, as previous molecular studies of the human genome concluded around 30 per cent.

The findings are the first to provide a measure of the influence that rare genetic variants have on intelligence.

The team also found that rare genetic variants accounted for a disproportionate amount of intelligence compared to more common genetic variants.

Dr David Hill said: 'We used two methods to measure the effect that rare variants had on intelligence.

'By combining the effect of both rare and common variants, more than 50% of the differences in intelligence between people could be traced to their genes.'

The study, published in the journal Molecular Psychiatry, is the first to demonstrate the influence rare genetic variants have on intelligence.

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As well as genes, environmental factors such as parenting, nutrition and exposure to chemicals in the womb are also thought to have a significant effect (stock image) 

The research follows a major breakthrough last year when scientists uncovered 52 genes linked to the intelligence trait, 40 of which were new discoveries.

An international research team led by Vrije Universiteit Amsterdam studied genetic data from over 78,000 individuals.

The data included information on DNA genotypes and intelligence scores, which led the team to discover new genes and biological routes for intelligence.

Scientists found that many people with these genes are more likely to have other traits, including being tall, thin and unlikely to smoke.

People who expressed the genes were less likely to suffer from Alzheimer's disease, depressive symptoms, schizophrenia and obesity.