Why Do People Get Autism? Genetic Link Between High Intelligence And Spectrum Disorder May Explain Evolutionary Survival

Is autism becoming more prevalent because it’s good for the future of humanity? New research suggests evolution is favoring the disorder: A study in PLOS Genetics says certain genetic mutations that are associated with an increased risk of autism were passed on during evolution because they are also associated with improved cognitive abilities.

According to the study, the researchers’ genetic analysis supports previous findings that people carrying autism genes tend to be intelligent, as well as findings about common traits between autism and high IQs — bigger brains that grow faster, better sensory and visual-spatial capabilities, and improved decision-making, to name a few.

Read: Air Pollution and the Risk of Autism

Based on what we know about evolution — the process through which a species passes on the genes that make their kind more successful while weeding out the negative traits — genes linked to psychiatric and developmental disorders should be part of that latter group, the study explains, “as they interfere with reproductive fitness.” But in some cases, they are not eradicated.

Autism Brain Autism may stem from outside of the brain, leading researchers to search the central nervous system for answers. Photo courtesy of Pixabay, public domain

The most harmful genes that predispose people to autism, which the study refers to as “rare disruptive variants,” are indeed marked for removal. It’s the more common genetic mutations that have a smaller effect that are making it through the genetic gauntlet.

“It might be difficult to imagine why the large number of gene variants that together give rise to traits like [autism spectrum disorder] are retained in human populations,” co-author and genetics and neuroscience professor Joel Gelernter said in a statement from Yale University. “The idea is that during evolution these variants that have positive effects on cognitive function were selected, but at a cost — in this case an increased risk of autism spectrum disorders.”

Read: A Brain Scan for Autism

 

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