Our genome contains traces of viral infections that occurred thousands of years ago. These DNA sequences can increase the risk of suffering from psychiatric disorders, such as schizophrenia.
- Traces of DNA from fossil viruses are present in our genome.
- The reactivation of these is associated with an increased risk of developing certain psychiatric disorders.
- The expression of these endogenous human retroviruses would have effects on brain function.
Our brain contains fossils: traces of viral infections that occurred hundreds of thousands of years ago. According to a study from King’s College London, the reactivation of these viruses could contribute to the appearance of certain psychiatric disorders. The authors develop this thesis in the journal Nature Communications.
“Fossil viruses” are present in our genome
“About 8% of our genome is made up of sequences called human endogenous retroviruses (HERVs), which are products of ancient viral infections that occurred hundreds of thousands of years agoexplain the authors in a press release. Until recently, it was thought that these ‘fossil viruses’ were just junk DNA, with no important function in the body..” In this work, the team used data from large genetic studies involving tens of thousands of people, with or without mental health problems. In parallel, it analyzed information from brain samples from autopsies of 800 people The aim of the British scientists was to understand how DNA variations linked to psychiatric disorders affect the expression of HERVs.
How do these virus DNA traces affect our mental health?
They discovered that “five robust HERV expression signatures” were associated with psychiatric disorders, including two linked to the risk of schizophrenia, one to the risk of bipolar disorder and schizophrenia, and one to the risk of depression. Concretely, this means that when these specific sets of HERVs are expressed in the human brain, this increases the risk of developing certain psychiatric disorders. “While it is unclear how these HERVs affect brain cells to cause this increased risk, our results suggest that their regulation of expression is important for brain function.”comments Dr Rodrigo Duarte, first author of the study and researcher from King’s College London.
Fossil viruses: towards better management of psychiatric disorders?
Dr Douglas Nixon, co-author of the study and researcher at the Feinstein Institute for Medical Research at Northwell Health, in the United States, recalls that additional research will be necessary to understand the exact role of HERVs in the appearance of psychiatric disorders. However, he believes that this discovery could have important consequences in the future. “We believe that a better understanding of these ancient viruses and the known genes involved in psychiatric disorders has the potential to revolutionize mental health research and lead to new ways of treating or diagnosing these illnesses.”he says.
