A scientific breakthrough has revealed the extent to which human intelligence is determined by our genes.

A recent study of almost 80,000 people – 60,000 adults and 20,000 children – uncovered 40 new genes that are linked to intelligence. This brings the number of genes known to have a bearing on our IQs to 52.

It’s believed that this newly unearthed haul of intelligence-linked genes can account for about 5% of difference in people’s IQs.

The researchers behind the study have added a caveat to this by stating that various other factors beyond genetics are known to contribute to our IQs and general intelligence.

Nevertheless, it’s hoped that this latest discovery could eventually enable scientists to better answer the nature versus nurture question when it comes to understanding the roots of our intelligence.

A DNA double helix is seen in an undated artist's illustration released by the National Human Genome Research Institute to Reuters on May 15, 2012. A group of 25 scientists June 2, 2016, proposed an ambitious project to create a synthetic human genome, or genetic blueprint, in an endeavor that is bound to raise concerns over the extent to which human life can or should be engineered.  REUTERS/National Human Genome Research Institute/Handout - RTX2FEXW
Scientists will have to scan millions of genomes to find all the other genes that are linked to intelligence
Image: REUTERS/National Human Genome Research Institute

Genetic analysis bears fruit

The research, which was led by Professor Danielle Posthuma from the VU University Medical Centre Amsterdam, was carried out using two different forms of genetic analysis.

A total of 40 of the overall number of genes found by both methods had not been previously implicated in intelligence.

One of the strongest correlations between genetics and intelligence were mutations found in a gene called FOXO3, and the coding that promotes its expression.

FOXO3 is part of a pathway that triggers cell death as a result of certain chemical stresses.

Interestingly, these same genes were also associated with better educational attainment, a larger head circumference at birth, living longer, and autism.

Other factors influence intelligence

Beyond genetics, many factors also play a part in determining a person’s IQ. These include everything from conditions in the womb, to nutrition, social environment and even pollution.

It’s possible that thousands of genes could be linked to intelligence, but getting to the bottom of this theory would require the scanning of millions of genomes.