Viruses in our chromosomes

Biologists have found a hidden retrovirus in human DNA

Alexey Ivanov, Rossiyskaya Gazeta

Human DNA contains parts of the genome of dozens of endogenous retroviruses (HERV), and one of them has been preserved completely and theoretically can be reproduced. This discovery was made by scientists from Tufts University and the University of Michigan Medical School, according to the university's website (More ancient viruses lurk in our DNA than we thought).

Biologists studied the genome of 2,500 people from all over the world, many of whom were volunteers from African countries, where it is believed that the ancestors of modern humans originated before migrating around the world. The team used sophisticated methods to compare key regions of each person's genome with a "reference" genome.

In total, 19 new DNA parts were found in 50 subjects, left by viruses that our ancestors infected hundreds of thousands of years ago. Scientists also confirmed the presence of 17 other parts of the DNA of viruses identified in the human genome by other researchers earlier. On one X chromosome, scientists found the entire viral genome intact, it was named Xq21. This is only the second intact ancient virus found in human DNA.

Endogenous human retroviruses belong to the same type of virus as AIDS, and approximately 8 percent of human DNA is actually traces of ancient viruses. In some cases, HERV sequences in the genome serve useful purposes, for example, helping pregnant women build a layer of cells around the fetus to protect it from toxins in the mother's blood.

"This discovery will allow us to study epidemics that occurred many, many years ago," says Tufts University virologist John Coffin. "It provides important information needed to understand how retroviruses and humans have evolved together in relatively recent times.

His colleague Geoffrey Kidd, a geneticist from the University of Michigan, in turn notes that retroviruses are remnants of ancient events that were not recorded in the population as a whole, but rather took place in the life of the ancestors of some living people.

The results of the work of American scientists are published in the journal Proceedings of the National Academy of Sciences (Wildschutte et al., Discovery of unfixed endogenous retrovirus insertions in diverse human populations).

Portal "Eternal youth" http://vechnayamolodost.ru  24.03.2016