A tiny tweak in brain chemistry may have been the secret to humanity’s success over our ancient ancestors, Neanderthals and Denisovans. A new study suggests that a single amino acid substitution in an enzyme called adenylosuccinate lyase (ADSL) could be the key.
The ADSL enzyme plays a crucial role in DNA synthesis and is made up of 484 amino acids. The difference between modern humans and our extinct cousins lies in a single amino acid, which changes the enzyme’s stability but not its function. Researchers from Japan and Germany studied the gene that codes for ADSL in genetically altered mice and found that those with the modern version of the enzyme had improved decision-making skills.
Female mice with the modern version were quicker and more successful at getting water when they were thirsty, suggesting that this small change may have helped our ancestors to compete effectively for resources. The study’s findings have sparked interest in understanding the role of ADSL in human behavior and cognition.
Researchers also discovered that nearly all modern humans carry genetic changes in the ADSL gene that don’t directly code for proteins. These changes appear to have been favored during human evolution, lowering the enzyme’s activity even further, especially in the brain. The study suggests that this small change may have given our species an evolutionary advantage over ancient hominins.
While it’s too early to translate these findings directly to humans, researchers believe that the substitution might have provided a competitive advantage in particular tasks relative to ancestral humans. Further studies are needed to understand the effects of ADSL on human behavior and cognition, but this study opens up new avenues for investigation into our species’ evolutionary history.
Source: https://www.iflscience.com/this-small-tweak-to-brain-chemistry-may-have-given-homo-sapiens-a-competitive-edge-80293