New research led by King’s College London has found that thousands of DNA sequences originating from ancient viral infections are expressed in the brain, with some contributing to susceptibility for psychiatric disorders such as schizophrenia, bipolar disorder, and depression.

Legacy of Ancient Viruses

About eight percent of our genome is comprised of sequences called Human Endogenous Retroviruses (HERVs), which are products of ancient viral infections that occurred hundreds of thousands of years ago. Until recently, it was assumed that these ‘fossil viruses’ were simply junk DNA, with no important function in the body. However, due to advances in genomics research, scientists have now discovered where in our DNA these fossil viruses are located, enabling us to better understand when they are expressed and what functions they may have.

Published in Nature Communications, the study was part-funded by the National Institute for Health and Care Research (NIHR) Maudsley Biomedical Research Centre and the US National Institutes of Health (NIH).

This new study builds upon these advances and is the first to show that a set of specific HERVs expressed in the human brain contribute to psychiatric disorder susceptibility, marking a step forward in understanding the complex genetic components that contribute to these conditions.

Continue here: Ancient Origins