The hallmark of a retrovirus is its ability to integrate its own genetic material permanently into the host's genome. This process occurs in several distinct stages:
Perhaps most surprisingly, retroviruses have played a massive role in human evolution. When a retrovirus infects a sperm or egg cell, its genetic material can be passed down to future generations. Over millions of years, these "fossil" viruses have accumulated in the human genome and are known as . Scientists estimate that 8% to 9% of the human genome is composed of these ancient viral remnants. While most are now inactive mutations, some have been repurposed by our bodies to help regulate the immune system or even aid in the development of the placenta during pregnancy. Conclusion Retrovirus
: The enzyme reverse transcriptase "back-transcribes" the viral RNA into a double-stranded DNA copy. The hallmark of a retrovirus is its ability
Because these viruses integrate into the host DNA, they are incredibly difficult to cure. Modern medicine manages these infections with , which targets specific enzymes like reverse transcriptase or protease to stop the virus from replicating. The "Fossil" Record in Our DNA Over millions of years, these "fossil" viruses have
Retroviruses are responsible for several significant human diseases. The most well-known is , which attacks the immune system's T-cells and can lead to AIDS . Other notable human retroviruses include:
: Finally, a protease enzyme cleaves the viral proteins into their functional forms, maturing the virus so it can infect new cells. Human Health and Diseases
: Another enzyme, integrase , carries this viral DNA into the cell's nucleus and "clips" it into the host's own DNA. At this stage, the integrated viral DNA is known as a provirus .