Genetic study sheds light on changes that shaped human brain evolution

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https://phys.org/news/2025-02-genetic-human-brain-evolution.html

9 Feb 2025

A new Yale study provides a fuller picture of the genetic changes that shaped the evolution of the human brain, and how the process differed from the evolution of chimpanzees.

For the study, published Jan. 30 in the journal Cell, researchers focused on a class of genetic switches known as Human Accelerated Regions (HARs), which regulate when, where, and at what level genes are expressed during evolution.

While past research theorized that HARs may act by controlling different genes in humans compared to chimpanzees, our closest primate relative, the new findings show that HARs fine-tune the expression of genes that are already shared between humans and chimpanzees, influencing how neurons are born, develop, and communicate with each other.

Using advanced techniques, researchers also were able to track how HARs interact with genes and human neural stem cells, which allowed them to identify gene targets for nearly all HARs—a significant advance in the study of human evolution.

The discovery adds to the growing understanding of how genetic changes arising during evolution made us human and significantly advances knowledge about what genes HARs controlled, said James Noonan, the Albert E. Kent Professor of Genetics at the Yale School of Medicine, who led the study.

"The results reveal that HARs largely regulate the same genes in both species, particularly those involved in brain development," Noonan said. "However, HARs adjust gene expression levels differently in humans, suggesting that evolutionary changes to brain function emerged not by reinventing genetic pathways but by modifying their output."


A human who is person of color and chimpanzee separated by dna strand
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