Study Showcases Certain Neanderthal Gene Variants Make an Individual More Susceptible to Autism
Neanderthals may have vanished a long time ago, but they continue to startle scientists with discoveries. The most recent finding implies that gifts from them could likely enhance susceptibility to autism in modern humans, as reported by Earth. Researchers believe that genes passed down by Neanderthals during interbreeding led to the facilitation of behavioral patterns often associated with this disorder. For the investigation, researchers compared whole-genome data acquired from autistic people, their unaffected siblings, and unrelated individuals. The team noted that in autistic individuals, certain Neanderthal-derived variants were more common compared to other participants. The investigation and its findings were published in detail within the journal Molecular Psychiatry.
How Did Neanderthal Genes Enter Modern Humans?
The interaction between modern humans and Neanderthals supposedly happened 50,000-60,000 years ago when the former were moving out of Africa into Eurasia. During this interaction, both groups exchanged tools and genes through interbreeding. Some of these variants have managed to survive for centuries, as experts claim that the modern human population derived from ancestors that eventually arrived in Eurasia carried around 2% Neanderthal DNA. Some of these ancestors also returned to Africa and spread the Neanderthal genes around the continent. These movements suggest that nearly every human on Earth has traces of Neanderthal genes, though the amount varies. Researchers have long been trying to understand how genes changed modern humans over the centuries, and may have found one of these transformations.
Genetic Study on Subjects
The whole genome data acquired from different groups showcased that individuals diagnosed with autism carried a greater quantity of specific Neanderthal genetic variants, according to Loyola University New Orleans. Researchers also detected which genetic markers were associated with autism in different ethnic groups. The investigation revealed that the Neanderthal DNA marker present in the SLC37A1 gene had associations with both autism and epilepsy in white non-Hispanic individuals.
Researchers clarified that the associations do not imply that autistic individuals have more Neanderthal DNA compared to their counterparts. Rather, it suggests that a subset of Neanderthal-derived genetic variations is more dominant in autistic individuals. "We are excited about the potential implications of these findings for autism research," shared co-author Dr. Emily Casanova, assistant professor of neuroscience at Loyola University New Orleans. "Understanding the role of Neanderthal DNA in autism could lead to new insights and approaches to diagnosis and a better understanding of the different causes of autism. One example of diagnostics would be the use of these markers in gene panels that could aid in the diagnosis of autism."
What Do These Variants Do?
These variants specifically control genes that monitor communications between different brain regions. In autistic individuals, the brain regions responsible for visual processing became more active during this communication. While the default mode network (a set of specific brain regions) that controls actions like social behavior and daydreaming was less active. The traits produced due to this 'connectivity' are often associated with autism, such as social fatigue and advanced visual observations.
Experts are not proposing that these Neanderthal gene variants cause autism. Instead, they believe it makes individuals more susceptible to this condition, according to Clemson News. "The hypothesis is not, 'Did Neanderthals give us autism?' It's that Neanderthals gave us some of the gene tweaks that give a higher susceptibility for autism," co-author Alex Feltus, a professor in the Clemson Department of Genetics and Biochemistry, shared. "Autism is a complex trait. It is controlled by many, many genes. A big part of what we do in my lab is try to understand the level of complexity. Of the 60,000 genes in the human genome, how many genes are at play when you're developing autism or cancer or any other complex trait? We embrace complexity. We don't try to erase complexity," he continued.