Dutch researchers have identified 52 genes associated with a variation in IQ In most cases, this role had never been highlighted.
Are you proud of your intelligence? You can thank your parents. In adulthood, 80% of our Intelligence Quotient (IQ) is inherited from our parents. But so far, the genes in question have been well hidden in our DNA. A Dutch team has finally brought them to light. In Nature Genetics, researchers at the University of Amsterdam describe the discovery of 52 genes associated with IQ.
Very present in the brain
Among these “new” genes correlated with intelligence, 40 had never been identified. The advance is therefore major. Especially since the majority of these DNA fragments are expressed in brain tissue. Achieving this result required painstaking work. Scientists analyzed the genome of 78,000 individuals from 13 cohort studies.
Some of the genes described in the study are not unknown to insiders. SHANK3, for example, has previously been linked to autism and schizophrenia. It is also involved in the formation of synapses, which allow communication between neurons. Others influence the development of axons, extensions of neurons, or the volume of certain regions.
“The genes that we have detected are involved in the regulation of cell development,” explains Danielle Posthuma, main author of this work. The researcher does not hide her enthusiasm. For her, “these results provide, for the first time, clear clues about the biological mechanisms underlying intelligence. “
A tiny fraction of genes
In fact, these genetic variations have a strong correlation with the level of schooling but also – to a lesser extent – with the intracranial volume or the circumference of the head. Conversely, a negative association emerges with several brain disorders (Alzheimer’s disease, depression, etc.) and overweight.
“Thus, the variant of a gene with a positive effect on intelligence has a negative effect on schizophrenia, BMI or obesity”, summarizes Suzanne Sniekers, who participated in the research.
Further work is planned to clarify the exact role of these genes on intelligence. The objective is to obtain a more precise idea of the role of these genetic variations on the different levels of IQ.
The work is far from over, according to Danielle Posthuma’s admission. “The current results explain up to 5% of the total variations in intelligence,” she emphasizes. We are therefore far from having brought to light all the modifications involved. According to the researchers, only larger studies will allow other associations to emerge. It’s like looking for a needle in a haystack.
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