Whether it’s a malicious computer program or a microscopic parasite, a virus always seems to have a negative connotation. I mean, the first thing you learn about them is how they can reproduce incredibly fast, with bad intentions. They contaminate a cell, and soon make thousands of copies of themselves, intent on infecting your whole body. Hearing this as a child, I always thought of viruses as something to be afraid of. Reading this article changed my mind.
Scientists have known that retroviruses (viruses composed of RNA) have been able to copy its own genes and transcribe them into new DNA. What they didn’t know was that these retroviruses are capable of infecting a sperm cell or egg, and of being passed down into the new generation. What is left are broken fragments of code. These fragments are pieces of viruses that have been passed down from our ancestors for generations. We call these endogenous retroviruses. These fragments do not really serve a purpose, or cause any harm to us, so they weren’t seen as important, that is until Thierry Heidmann and his colleagues managed to take these broken parts of the virus, and align them back. This newly assembled virus shed the light on how we evolved. Contrary to Darwin’s belief, natural selection is not the only way we humans can evolve. He believed that our traits are chosen based on selective pressures, that determine if something is advantageous or not. Darwin never knew of the huge role endogenous retroviruses played in our evolution. He didn’t know that without pathogens, humans might have never developed a placenta.
The one thing I found most surprising about this article is the fact that viruses had such a huge role in our evolution. Thinking of all of the terrible viruses like HIV and Ebola, I always thought that they were just evil parasites that were not needed in this world. Reading through the article, especially the part about how our body is full of retrovirus fragments and how over the years of evolution, they have been defeated, it really got me thinking. I thought about how powerful evolution and diversity actually is. This means that someday the HIV virus will be nothing but a fragment found in our DNA, harmless and not important.
The article suggests that viruses have played a big role in evolution, especially since they have formed us into the humans we are now. The article said that almost 10 percent of our DNA consists of old retroviruses. Each fragment of the retrovirus is like a piece of history embedded in our DNA forever. Although viruses may be causing harm now, I think it is nice to think that one day they will contribute something better to our evolution. I used to think that viruses were all bad, but learning new information about them made me change my mind. Sure, humans have suffered millions of years ago from viruses, but we survived, and we grew stronger. The pieces of retrovirus fragments left in our body are examples of that.
I think that reviving old viruses has helped scientists understand a lot more about the lineage of primates, and the relationship between animals. They can also use the old retroviruses to figure out how to create defenses against new retroviruses. New versions of the viruses can be assembled to learn how we become immune to it. This would help with new viruses like HIV, that are difficult to understand. The TRIM5A protein protects monkeys from HIV, but in humans it protects from the PtERV virus. Reconstructing this gene might help protect humans from the HIV virus and help to find a drug that acts like the monkey protein.
Reading this article really changed my opinion on viruses. I went from being disgusted by them, to being in awe. There are so many things about us that are so unusual, and it’s so interesting to learn something new everyday. If Darwin were here, he would probably be hyperventilating right now.