The Genetic Basis of Human Cognitive Superiority Compared to Other Primate Species

Recent research led by the University of Toronto has identified a group of 139 genes that are uniquely expressed in human brains, distinguishing us from other primates such as orangutans, gorillas, chimpanzees, and bonobos. The findings of this study were published in Nature Ecology & Evolution.

The study focused on the expansion of the brain’s cerebral cortex and increased cellular diversity post our evolutionary split from other primates, attributing these developments to our unique cognitive abilities. The research involved the analysis of single-cell sequencing data from the BRAIN Initiative Cell Census Network, examining samples from the middle temporal gyrus of the brains of various primate species, including humans, chimpanzees, gorillas, macaques, and marmosets.

The analysis revealed a subset of 139 genes with markedly different expression patterns in human brains compared to other primate brains. These genes have undergone intense evolutionary divergence in human brains, and are more resilient to mutations without affecting their function. This suggests they may have been subject to less stringent evolutionary selective pressure, allowing them to potentially underpin higher cognitive capabilities.

Hamsini Suresh, the first author of the study and a research associate at the Donnelly Centre for Cellular and Biomolecular Research, emphasized the importance of genetic tolerance to change in the human brain, stating that it allows for rapid evolutionary changes.

The divergent genes were found in 57 different types of brain cells, with a quarter of the genes showing distinct expression only in neuronal cells and the remaining half in glial cells. Approximately 25% of the genes that differ in humans are associated with various brain disorders, shedding light on the genetic basis of neurological conditions.

The senior author of the study, Jesse Gillis, noted that the findings not only contribute to our understanding of the differences between human and primate brains at a cellular level, but also provide a database for further genetic comparisons across primates. The researchers have made their extensive single-cell gene expression catalogs available online, paving the way for new evolutionary analyses.

This research has the potential to open up new avenues for investigating the evolution and disease in primates from a genetic perspective. The full research article can be found in Nature Ecology & Evolution. For more cutting-edge scientific discoveries, subscribe to Technology Networks’ daily newsletter, delivering breaking science news straight to your inbox every day.