HAR123 linked to human brain traits

A regulatory DNA element HAR123 may help explain what makes the human brain distinct.

Genetic Switch May Be Key to Human Brain's Unique Abilities

Researchers at UC San Diego School of Medicine report that HAR123, a human accelerated region in the 17p13.3 area, functions as a neural enhancer that shapes the formation of neural progenitor cells and the neuron to glia ratio. The human version of HAR123 differs from the chimpanzee version in the genes it regulates, suggesting a regulatory route to brain evolution. The findings come from experiments in human stem cells and neuron precursors and point to a molecular mechanism that could contribute to human-specific neural traits.

The study also links HAR123 to cognitive flexibility, the ability to unlearn and adapt to new information, and notes potential connections to neurodevelopmental disorders such as autism. While these results illuminate a possible genetic pathway behind brain differences, the researchers caution that much work remains to confirm effects in living brains and to understand how HAR123 acts in vivo.

The work highlights how small stretches of non coding DNA can steer big brain traits, shifting attention from genes to when and where they are turned on. It underscores a growing trend in neuroscience: regulatory elements may drive much of what makes human cognition unique.

Yet the claims are early. In vitro results do not guarantee the same outcomes in a living brain, and many genes interact in complex networks. Communicating these findings responsibly is essential to prevent over interpretation or misperceptions about human differences and neurodevelopmental disorders.

Highlights

As science moves from genes to regulatory switches, our understanding of the brain will keep evolving.