Germs down the generations
A relatively tiny group of human ancestors, living around 24,000 years ago, are responsible for transmitting an inherited strain of human herpesvirus, known as HHV-6, that still affects millions of people around the world today, scientists at the University of Leicester have discovered.
HHV6 is unusual because it can insert itself into the genome and lie low, unlike other herpes viruses, which hide inside neurones and other cells types but don’t usually integrate into our DNA. This also means that they can be passed on down the generations, if they’ve inserted into a cell that will become egg or sperm.
After studying the viral DNA inserted in the genomes of people from the UK, Europe, Japan, China and Pakistan, the scientists found that some of the inherited viruses were very similar to each other and are also located in the same part of the genome in people who weren’t known to be immediately related.
By comparing subtle changes in the virus DNA that had accumulated over thousands of years, the researchers concluded that these viral infections originated in a small number of ancestors thousands of years ago. And although the infection is ancient, up to two per cent of the UK population today carry inherited HHV6, and there are concerns it could reactivate and cause health problems. Understanding more about the genetic legacy of the virus will help to identify its long term effects on health.