19 New DNA fragments—leaved by viruses that first infected our ancestors hundreds of thousands of years ago—had just been discovered, lurking between our own genes.
published in the Proceedings of the National Academy of Sciences , the scientists of , said that of the 2,500 people studied, fragments containing all the genetic information of the complete virus were found in the DNA of about 50 of them.
Whether it can be copied or reproduced is not yet clear. But studies on ancient viral DNA show that it can affect the humans carrying it. In addition to discovering these new fragments, scientists have also confirmed 18 other viral DNAs found in the human genome in recent years by other scientists.
This study looks at the entire DNA or genome range of people from around the world, including a large number of people from Africa—the ancestors of modern humans originated in Africa before migration. The team used complex techniques to compare key regions of each person's genome to the human genome.
These findings increase scientific knowledge of human endogenous retrovirus (HERV). This is the name of ancient infectious viruses that insert translated copies of DNA-based genetic material into the genome of our ancestors. They belong to the same type of virus, including HIV, a modern human immunodeficiency virus that causes AIDS .
For generations, the DNA produced by the virus has been continuously copied and inherited when humans reproduce. That’s how it ends in our DNA today. In fact, about 8% of what we think is “human” DNA actually comes from viruses. In some cases, the human body has adopted HERV sequences for useful purposes, such as helping the pregnant woman’s body establish a cell layer around the developing fetus to protect it from toxins in the mother’s blood.
The new HERV is part of the HERV-K family. The whole viral genome or provirus just discovered is located on X chromosome ; it is called Xq21. This is just the second complete provirus found to be hidden in human DNA.
"This looks like it is able to make an infectious virus, and if that's true, it would be very exciting because it can allow us to study viral epidemics that happened a long time ago," said senior author and virologist Dr. John Cofen. "This study provides important information necessary to understand how retroviruses and humans evolve together in relatively recent times."
