This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Humans and chimpanzees share almost all their genes. Despite this, our brains have developed in different ways.
Researchers at Lund University in Sweden have now shown that a viral pandemic dating back several million years is likely to be part of the explanation. Pandemics can arise wherever animal or human populations are sufficiently large, and they are not confined to the modern age. Johan Jakobsson, professor of molecular neurogenetics at Lund University, believes that the findings from the new study are highly relevant: They show that a virus can cause a DNA sequence to change across an entire population.
"The virus we investigated specifically affected chimpanzees. Yet humans and chimpanzees have largely the same genetic makeup. That is why it is important to understand the differences in how genes are regulated.
Our findings suggest that one gene, LINC00662, plays a significant role in early human brain development," says Jakobsson. This, Jakobsson adds, helps our understanding of how gene regulation can protect or damage, for example, the brain. In the new study, published in Science Advances, the researchers have discovered that an ancient viral remnant in the chimpanzee genome silences the LINC00662 gene.
The same gene, meanwhile, is active in humans and plays an important role in our early brain development. The viral remnant belongs to a so-called endogenous retrovirus, PTERV1—a virus that infected the chimpanzee population millions of years ago. The PTERV1 virus's genetic material remained in the genome and has since been passed down through the generations.
The researchers observed that PTERV1 replicated itself in many locations within the chimpanzee's DNA and that these viral sequences are systematically silenced through a process known as methylation—a mechanism that determines which genes are active or inactive. To investigate how the viral remnant affects brain development, the researchers used human and chimpanzee stem cells to create brain organoids. These three-dimensional miniature organs resemble real brain tissue and can display certain characteristics of early brain development.
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