# Ancient retrovirus and primate brain evolution > Developing situation record from CLSTR: https://clstr.news/situations/ancient-retrovirus-and-primate-brain-evolution > Updated: 2026-10-31T01:39:01.000Z. Sources: 2. Developments: 2. Researchers at Lund University have identified an ancient endogenous retrovirus, PTERV1, that may have influenced the divergent evolutionary paths of human and chimpanzee brains. The virus, which inserted genetic material into ancestral African apes approximately 4 million years ago, is present in the chimpanzee genome but absent in humans. Studies indicate that these viral remnants can alter the regulation of nearby genes. Specifically, the PTERV1 sequence in chimpanzees is located near the LINC00662 gene. While this gene is active during early human brain development, it remains silent in chimpanzees. Using CRISPR technology to remove the viral sequence from chimpanzee cells, researchers were able to reactivate the gene. Additionally, experiments with brain organoids demonstrated that deactivating the LINC00662 gene in human brain models decreases the activity of genes responsible for nerve cell formation and connectivity. This suggests the viral trace plays a significant role in suppressing gene expression in chimpanzees. ## Timeline ### 2026-10-31: Researchers link ancient virus to brain development differences Lund University researchers found that an ancient virus, PTERV1, may suppress a key gene in chimpanzees that is active in human brain development, potentially explaining neurological differences. 2 sources. https://clstr.news/cluster/researchers-link-ancient-virus-to-brain-development-differences ### 2026-10-23: Ancient retrovirus may have influenced human and chimpanzee brain evolution A study suggests an ancient retrovirus (PTERV1) left genetic traces in chimpanzees that may have altered brain development, contributing to the evolutionary divergence between humans and chimps. 4 sources. https://clstr.news/cluster/ancient-retrovirus-may-have-influenced-human-and-chimpanzee-brain-evolution --- Cite as: Ancient retrovirus and primate brain evolution. CLSTR, https://clstr.news/situations/ancient-retrovirus-and-primate-brain-evolution