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Is IQ Inherited? 10 Genetic Mutations May Account For Intelligence And Explain Dementia

Is IQ Inherited? 10 Genetic Mutations May Account For Intelligence And Explain Manifestation Of Dementia
Researchers studied the small genetic mutations of more than 126,000 individuals to determine how their genes influenced their educational achievements. Creative Commons

An extensive study involving more than 126,000 people found that small mutations in the DNA could influence a person's intelligence.

A global team of 200 researchers identified 10 SNPs, or small mutations found in DNA, that accounted for individuals' educational achievements. However, no one particular gene was pinpinted to strongly influence IQ.

"Our study shows that the effects of every single genetic variant on educational attainment are much smaller than many scientists expected," said Philipp Koellinger, co-author and associate professor of Erasmus School of Economics at Erasmus University Rotterdam in the Netherlands. "But finding these genetic variants is still important because it may lead to insights into biological pathways underlying human behavior."

The research team studied 2.5 million SNPs found in the participants' genomes, and found that three strongly and seven weakly correlated genetic variations had accounted for their educational achievement, which they used as a measurement for intelligence, but only by two to three percent. The strongest SNPs only explained 0.02 percent of a person's intelligence, while all the SNPs could essentially account for up to 20 percent of a person's intelligence if a larger number of participants were used.

SNPs are the most common genetic differences among people. Based on this, researchers found that looking at these genetic variations could be associated with the number of years of schooling and whether the person earned a college degree.

"Educational attainment, like most human behaviour, is influenced both by environmental and genetic factors," Koellinger said. "Our study is a first step to identify some of these genetic factors. The genetic associations we discovered are only a very small piece of a very large puzzle. But our findings do have a number of significant implications."

The researchers said a larger sample size of participants and more studies are needed to strengthen this finding, but it may provide tools to study aging of the brain and why certain individuals are more genetically disposed to develop dementia, the decline in mental ability and memory.

"In the future, a better understanding of these biological pathways may also help us to gain new insights into how the environment and genes together influence socio-economic and medical outcomes," said Koellinger.

 

Source: Rietveld CA, Medland SE, Derringer J, et al. GWAS of 126,559 individuals identifies genetic variants associated with educational attainment. Science. 2013.

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