In a breakthrough study published in the scientific journal Nature Genetics, they have found many new genes that have been identified for the first time and their link to human intelligence. The main author of the study was a researcher at Amsterdam's Center for Neurogenomics and Cognitive Research, Danielle Posthuma. As she said about the importance of the study, "For the first time, we were able to detect a substantial amount of genetic effects in IQ."

What the study found in regard to genes and intelligence

Scientists announced that they discovered 52 genes that were linked to intelligence in humans.

This included 40 genes that were identified for the first time as having a link to human intelligence. Taken together, this new batch of so-called "smart genes" accounted for 20% of the disparity in intelligence quotient (IQ) test results among 78,000 people that were analyzed in 13 earlier studies.

A large chunk of these 40 newly discovered gene variants are connected to an elevated IQ. They also play a role in managing cell development in the brain. They were found to be principally associated with neuron differentiation and the formation of neural information gateways called synapses in the brain.

Autism and 'smart genes'

The study also found a surprising association between autism and intelligence that scientists hope could one day clarify the origin of the condition.

A lot of the genetic variants linked to higher IQ also match up with other characteristics. These include more years spent getting an education, larger head size in infancy, and height, among others. However, one of the strongest links, which shocked scientists, was between autism and high IQ.

The research found that gene variants that are associated with high IQ also correspond with a higher risk of being on the autism spectrum disorder.

Apparently, one gene in particular, SHANK3, looks like it could be a very good candidate for explaining why that is. In the opposite direction, the lack of certain high IQ genes was found to be more common in people that suffered from schizophrenia and obesity.

Genetic IQ test

As mentioned above, the scientists who did the study went through 13 earlier studies that each used different IQ tests from a total of 78,000 people, all of European descent.

They then matched these tests against the 52 gene variants to get their 20% number mentioned above. The scientists still said that even though these appear to be the 52 main genes behind IQ, there could still be more out there.