A new research has revealed that fewer viral relics in human genes may be due to a less bloody evolutionary history.
A team of researchers from the University of Oxford and Plymouth University found that humans have fewer remnants of viral DNA in their genes compared to other mammals may be because of reduced exposure to blood-borne viruses as humans evolved to use tools rather than biting during violent conflict and the hunting of animals.
The researchers compared the genetic signature of the two edges of the virus. These edges are identical when the virus first invades the genome, but as they acquire random mutations over time, they slowly begin to diverge. By tracking this divergence, the research team could measure how long the retrovirus had spent in an animal's genome.
They found that, compared to other animals, far fewer retroviruses were incorporated into the genome for humans and other apes over the last 10 million years. Even compared to animals very similar to us, humans are unusual in not having acquired any new types of retroviruses into their DNA over the last 30 million years.
Researcher Robert Belshaw said that considering us simply as a primate species, the proportion of human individuals that are infected with retroviruses is much less than among our relatives such as chimpanzees.
However, lead researcher Gkikas Magiorkinis said that they have shown in the past that Hepatitis C, a virus transmitted mainly through blood, was spread massively after World War II. There is no doubt that the past trend of reduced blood contacts has been reversed in the last century, and this has severe consequences for viral infections.
The study appears in the journal Retrovirology.