Ancient retrovirus may have influenced human and chimpanzee brain evolution

Researchers have identified an ancient viral infection that may explain the divergent evolutionary paths of human and chimpanzee brains. A study published in Science Advances suggests that an endogenous retrovirus, known as PTERV1, inserted genetic material into the genomes of ancestral African apes approximately 4 million years ago.

While humans and chimpanzees share roughly 98.8 percent of their DNA, the human brain is approximately three times larger and possesses significantly different cognitive capabilities. The study, led by researchers at Lund University, indicates that PTERV1 is present in the chimpanzee genome but entirely absent in humans. These viral remnants, which make up at least 8 percent of both species' genomes, can alter how nearby genes are regulated.

By examining the parts of the genome that control gene expression rather than just protein-coding genes, scientists found that these viral insertions appear to influence genes involved in neuron development. The absence of PTERV1 in the human lineage may be due to different ancestral habitats or the protection provided by the antiviral protein TRIM5α.