Alteration in Brain Chemistry Possibly Granted Homo Sapiens a Competitive Advantage
Single Amino Acid Change in ADSL Enzyme May Have Given Modern Humans a Competitive Advantage
Researchers have discovered a significant genetic difference between modern humans and extinct hominins like Neanderthals and Denisovans, which could have influenced brain chemistry and behavior. The difference lies in a single amino acid substitution in the adenylosuccinate lyase (ADSL) enzyme.
This enzyme, made up of 484 amino acids, plays a crucial role in the synthesis of DNA, RNA, and other important biomolecules. In modern humans, the enzyme at position 429 is an alanine, while in Neanderthals and Denisovans, it is a valine. This small change reduces the activity of the ADSL enzyme, especially in the brain.
The researchers hypothesize that this reduced activity might have subtly altered neural circuits, potentially enhancing certain brain functions like problem-solving, cognitive flexibility, or social behaviors. These functions are crucial for survival and adaptation. The genetic changes in the ADSL gene in modern humans, which don't directly code for proteins, were favored during human evolution, showing strong signals of positive selection.
In an experiment, scientists wanted to see if this change might affect behavior. They set up an experiment where mice had to respond to a sound or visual cue to get water. Only female mice with the modern version of ADSL showed a competitive advantage, being quicker and more successful at getting the water when they were thirsty. This suggests that this small change might help improve decision-making or competitiveness when resources are scarce.
However, the study's findings are too early to be translated directly to humans, as the neural circuits of mice are vastly different. The study, published in the journal Proceedings of the National Academy of Sciences, suggests that there are a small number of enzymes affected by evolutionary changes in the ancestors of modern humans, and ADSL is one of them.
Researchers from the Okinawa Institute of Science and Technology in Japan and the Max Planck Institute for Evolutionary Anthropology ran experiments on genetically altered mice to study the effects of the modern ADSL variant. They found that in these mice, there was a buildup of certain molecules, especially in the brain, due to reduced enzyme activity. Furthermore, the altered version of ADSL in modern humans emerges after our species split from other hominins but before modern humans migrated out of Africa.
Professor Svante Pääbo, one of the researchers, concludes that they are beginning to understand the effects of some of these changes and are puzzling together how our metabolism has changed over time. More studies are needed to understand the role of ADSL in behavior, and the researchers plan to study the effects of combinations of these evolutionary changes on metabolism over the past half million years of human evolution.
- The single amino acid change in the ADSL enzyme, found in modern humans but not in extinct hominins like Neanderthals and Denisovans, has been attributed to changes in brain chemistry and behavior, possibly due to its role in the synthesis of DNA, RNA, and other biomolecules.
- The reduced activity of the ADSL enzyme, specifically in the brain of modern humans, might have subtly altered neural circuits, potentially enhancing cognitive functions such as problem-solving, cognitive flexibility, or social behaviors.
- In a study published in the Proceedings of the National Academy of Sciences, researchers from the Okinawa Institute of Science and Technology in Japan and the Max Planck Institute for Evolutionary Anthropology found that the modern ADSL variant leads to a buildup of certain molecules, particularly in the brain, due to reduced enzyme activity.
- The reduced activity of ADSL enzyme, which emerged in modern humans after they split from other hominins but before they migrated out of Africa, is one example of how evolutionary changes in enzymes may have impacted the metabolism and behavior of modern humans over time.
- As researchers continue to study the effects of ADSL in behavior, more focus is being given to understanding the role of technology, science, neuroscience, and anthropology in elucidating the impact of genetic changes on health-and-wellness, medical-conditions, and the overall evolution of modern humans.
