Traces of ancient viruses which infected our ancestors millions of years ago are more widespread in us than previously thought.
A study shows how extensively viruses from as far back as the dinosaur era still thrive in our genetic material.
It sheds light on the origins of a big proportion of our genetic material, much of which is still not understood.
The scientists investigated the genomes of 38 mammals including humans, mice, rats, elephants and dolphins.
The research was carried out at Oxford University, the Aaron Diamond AIDS Research Centre in New York and the Rega Institute in Belgium.
It is reported in the journal Proceedings of the National Academy of Sciences.
One of the viruses was found to have invaded the genome of a common ancestor around 100 million years ago with its remnants discovered in almost every mammal in the study.
Another infected an early primate with the result that it was found in apes, humans and other primates as well.
The work established that many of these viruses lost the ability to transfer from one cell to another.
Instead they evolved to stay within their host cell where they have profilerated very effectively – spending their entire life cycle within the cell.
The researchers found evidence of the viruses multiplying so extensively within mammals’ genomes that they have been compared to an outbreak of disease.
The senior author of the study, Dr Robert Belshaw from Oxford University’s Zoology Department, said: “This is the story of an epidemic within every animal’s genome, a story which has been going on for 100 million years and which continues today.
The study shows that the viruses involved have lost a gene called Env, which is responsible for transmission between cells.
BBC has the full article
