Ancient Viruses Hacked Human Brains
A new study from Lund University in Sweden indicates that inherited viruses that are millions of years old play an important role in building up the complex networks that characterize the human brain.
The open access study, titled “TRIM28 Represses Transcription of Endogenous Retroviruses in Neural Progenitor Cells,” is published on Cell Reports.
The Viruses Took The Steering Wheel in Our Cellular Machinery
Johan Jakobsson, head of the research team for molecular neurogenetics at Lund University, said:
We have been able to observe that these viruses are activated specifically in the brain cells and have an important regulatory role. We believe that the role of retroviruses can contribute to explaining why brain cells in particular are so dynamic and multifaceted in their function. It may also be the case that the viruses’ more or less complex functions in various species can help us to understand why we are so different.
Researchers have long been aware that endogenous retroviruses constitute around five per cent of our DNA. For many years, they were considered junk DNA of no real use, a side-effect of our evolutionary journey. On the contrary, the Lund study shows that retroviruses seem to play a central role in the basic functions of the brain – over the course of evolution, the viruses took an increasingly firm hold on the steering wheel in our cellular machinery. In particular, the retroviruses seem to play an important role in the regulation of which genes are to be expressed, and when.
I believe that this can lead to new, exciting studies on the diseases of the brain. Currently, when we look for genetic factors linked to various diseases, we usually look for the genes we are familiar with, which make up a mere two per cent of the genome. Now we are opening up the possibility of looking at a much larger part of the genetic material which was previously considered unimportant. The image of the brain becomes more complex, but the area in which to search for errors linked to diseases with a genetic component, such as neurodegenerative diseases, psychiatric illness and brain tumors, also increases.
Recently, a new Artificial Intelligence (AI) system has used machine learning techniques to “learn” how to analyze large regions of the genome that previously could not be explored. So far, most researchers interested in the genetic roots of diseases have only analyzed the 2 percent of the human genome that includes protein-coding DNA sequences. But that, according to the creator of the AI program, is a relatively easy “low-hanging fruit.”
Images from Shutterstock.