Tiny genetic tweak may explain why humans outlasted Neanderthals

A small but significant difference in brain chemistry could be part of the reason Homo sapiens outlasted their ancient relatives, a new study suggests.

In research published on August 4 in the Proceedings of the National Academy of Sciences, an international team of scientists examined a human gene variant absent in Neanderthals and Denisovans — two extinct hominin species that once coexisted with early humans, Caliber.Az reports via foreign media.

The focus was on a gene called ADSL, which plays a role in brain function. In modern humans, a specific form of this gene produces a slightly less stable enzyme than the one found in our extinct cousins. When researchers inserted the modern version of ADSL into mice, female mice exhibited altered behaviour, becoming better at locating water — a possible indicator of cognitive shift.

While the study doesn't provide definitive answers, it offers a compelling clue into how subtle changes in brain biochemistry may have helped our species survive and thrive while others disappeared.

ADSL is already known to cause severe brain dysfunction in rare modern human mutations, with symptoms resembling autism and seizures. This led scientists to investigate whether a milder, ancient version of the gene could have contributed to behavioural or cognitive advantages.

“There is some fundamental difference between modern humans and other earlier forms of humans,” said Svante Pääbo, a Nobel-winning geneticist at the Max Planck Institute for Evolutionary Anthropology and co-leader of the study. “Neanderthals and Denisovans never became more than a few hundred thousand people at any one time, their technology over hundreds of thousands of years hardly changed — and that modern humans in just a hundred thousand years spread all over the planet, became millions of people and developed technology and culture that changed so rapidly.”

The findings point to the possibility that even tiny genetic tweaks may have profoundly shaped the course of human evolution.

By Vugar Khalilov