2025-09-28T05:47:58Z

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Have you ever wondered why Autism Spectrum Disorder (ASD) appears to be so prevalent among humans? A groundbreaking study from Oxford University Press reveals that our evolutionary journey might hold the key to understanding this phenomenon.

Currently, about one in 31 children in the United States is diagnosed with ASD, equating to around 3.2%. Globally, the World Health Organization estimates the figure at approximately one in 100. Interestingly, researchers believe that traits associated with autism are largely unique to humans, with very few signs of similar behaviors found in non-human primates. This points to a fascinating intersection between our evolution and neurodiversity.

The study highlights the importance of genomic evolution in shaping the human brain. Thanks to advancements like single-cell RNA sequencing, scientists can now explore specific cell types within the brain. This cutting-edge technology has unveiled a treasure trove of neuronal cell types unique to mammals, and specifically to humans.

As these researchers dove into extensive datasets, they discovered that certain neuron types in the outer layer of the human brain, particularly L2/3 IT neurons, evolved at a remarkably fast pace compared to our closest relatives, the apes. What’s even more intriguing is that this rapid evolution aligned with significant changes in genes linked to autism. It seems that natural selection played a role in this process, but why these genetic traits offered advantages to early humans remains a mystery.

Understanding the exact features that set humans apart cognitively and anatomically is complex. However, it is speculated that the genetic shifts associated with autism may have contributed to slower postnatal brain development. This could explain the protracted childhood we experience, fostering enhanced cognitive capabilities.

Lead researcher Alexander L. Starr poignantly states, “Our results suggest that some of the same genetic changes that make the human brain unique also made humans more neurodiverse.” In other words, traits we often view as challenges may actually represent evolutionary adaptations that shaped our species.