What if the secret to human intelligence could be traced back to just a handful of genetic differences?
A recent study has brought us closer to answering this question by uncovering a tiny stretch of human DNA that significantly boosts brain growth.
Scientists at Duke University have successfully inserted this DNA into mouse embryos, leading to a remarkable 12% increase in brain size.
This discovery not only sheds light on what makes human brains unique but also opens up new possibilities for understanding cognitive evolution and development.
The Discovery That Changes Everything
Humans share roughly 98% of their DNA with chimpanzees, yet our cognitive abilities far exceed those of our closest relatives.
This discrepancy has long puzzled scientists.
One major factor behind our intelligence is the rapid expansion of white matter in the first two years of life, which allows for an explosion of neural connections.
But pinpointing the exact genetic elements responsible for this phenomenon has remained elusive—until now.
By comparing human and chimpanzee DNA, researchers identified key differences in ‘enhancer’ sequences—short sections of DNA that control the activity of nearby genes.
Out of 106 potential enhancers, six were found to be near genes associated with brain development.
The most intriguing of these, dubbed HARE5, demonstrated an astonishing effect when introduced into mouse embryos: the resulting mice developed significantly larger brains than those with chimpanzee HARE5.
Intelligence and Evolution
For decades, scientists have debated whether brain size directly correlates with intelligence.
While brain size alone does not guarantee advanced cognitive functions, the structure and complexity of neural networks certainly play a crucial role.
The findings from this study disrupt long-standing assumptions by showing that a relatively small genetic modification can significantly influence brain growth.
Debra Silver, the lead study author and assistant professor of molecular genetics and microbiology at Duke, explained:
“We discovered that the human DNA sequence, which only had 16 changes compared to the chimp sequence, was being expressed differently in mice. The human DNA was really able to accelerate the way stem cells divide, and as a result, the mice were able to produce more neurons.”
This revelation challenges the belief that intelligence is merely a byproduct of gradual evolutionary changes.
Instead, it suggests that specific genetic enhancements, even minor ones, can have profound effects on brain development.
Are We on the Verge of Creating Smarter Animals?
One of the most surprising aspects of this discovery is the role of HARE5 in the development of the cerebral cortex—the region of the brain responsible for language, reasoning, and decision-making.
This raises intriguing questions about the potential impact of similar genetic modifications in other species.
Could this knowledge one day lead to enhanced cognitive abilities in animals?
Could we eventually manipulate our own genetics to boost intelligence further?
Silver and her team are already considering the next steps. As she told The Washington Post:
“We’re definitely interested in testing whether it might affect memory or socialization in mice.”
While we are still far from creating hyper-intelligent animals, these findings provide a critical piece of the puzzle in understanding how human intelligence evolved.
By continuing to explore genetic enhancers like HARE5, scientists hope to unlock the full potential of the human brain—and perhaps even rewrite the future of cognitive evolution.
Source: The Washington Post
