When we think of Neanderthals, we often picture bulky figures with heavy brows, dressed in fur and wielding stone tools. Surprisingly, some of their DNA still lingers in our genes today. Recent studies suggest that certain genetic traits passed from Neanderthals could be associated with autism spectrum disorder (ASD).
About 50,000 to 60,000 years ago, small groups of modern humans migrated from Africa into Eurasia. They encountered Neanderthals, exchanged tools, and engaged in interbreeding. This mixed heritage left an imprint: approximately 2% of the DNA in people of Eurasian descent is Neanderthal. Some of these genes re-entered Africa when descendants traveled back, scattering a lighter trace of Neanderthal DNA across the continent.
This genetic mix means most people today have at least a little Neanderthal ancestry, although the amount varies widely. Some of these genetic remnants are beneficial—they can enhance immunity or help us adapt to high altitudes. Yet, many others did not fit well with modern human biology and were eventually eliminated through natural selection.
Interestingly, a recent study led by Clemson University and Loyola University examined the relationship between Neanderthal DNA and autism. They analyzed genome data from autistic individuals and their unaffected siblings, revealing that specific Neanderthal gene variants were more common in those with autism. Notably, these variants were tied to brain functioning and connectivity.
Functional MRI scans backed this up. Participants with more Neanderthal gene snippets showed enhanced activity in visual processing areas of the brain. In contrast, areas related to social engagement showed less activity. This suggests that those traits might align with how many autistic individuals navigate the world—often excelling at pattern recognition while sometimes struggling with social interactions.
Archaeologists have noted that Neanderthals were skilled toolmakers, requiring meticulous planning and focus—similar strengths often seen in those on the autism spectrum. So why do these Neanderthal genes persist in some modern humans? Some experts suggest that in small, close-knit groups, the ability to observe and interpret the environment might have outweighed the challenges of complex social interactions.
This research doesn’t claim that Neanderthal DNA directly causes autism. Instead, it indicates that certain inherited traits can increase the likelihood of specific characteristics tied to autism. These features could have provided advantages in ancient environments and still benefit individuals today in fields like science, technology, engineering, and art (STEM).
Ultimately, the study highlights that genetics plays an important role in understanding autism. However, it is only part of the larger picture, which includes environmental factors and early development. Recognizing Neanderthal contributions sheds light on why autism exists worldwide across various cultures. It also suggests that our neurodiversity is rooted in our complex ancestry, making it a shared human trait rather than an isolated phenomenon.
As research progresses, experts hope to explore further how ancient genes influence brain development and intelligence today. The findings reflect that our evolutionary journey did not end with the rise of one species over another; rather, it woven a complex narrative of strengths and adaptations that shape our capabilities today.
The full study can be found in the journal Molecular Psychiatry.