This article on how viruses have affected evolution was a fascinating read. I think that this article is titled “Darwin’s Surprise” because Darwin would never have expected to find that after he collected such extensive evidence to support his theory of natural selection in fact, “nothing provides more convincing evidence for the ‘theory’ of evolution than the viruses contained within our DNA”. I think he would have found it the most surprising that many of the commonalities between the DNA of apes and humans are retroviral DNA, which would have to have been inherited from a common ancestor. If anything, I think he would have been, as the article suggests, excited and intrigued by these discoveries, at least after he got over his initial surprise. What I found most surprising about this article is that more of our DNA is made up of old retroviruses than is made up of DNA that codes for proteins, about ten percent versus less than two percent respectively. I guess it’s hard for me to imagine the length of a DNA strand in order to make sense of the idea that only two percent of our DNA codes for the millions of different functions that are carried out in the human body. It’s also a bit frightening to think that so much of my DNA is composed of viruses, which I usually associate with the negative experience of being sick. After reading this article, however, I definitely have a new understanding of how viruses can affect the human race.
The article suggests that viruses played a major role in evolution. Viruses might be the reason that mammals developed the placenta, which has definitely been a benefit to mammals. Scientists found that a protein that causes placental cells to fuse together uses the same mechanism that retroviruses use to attach to cells that they infect. The evolution of the placenta led to live birth, which the article explains is “one of the hallmarks of our evolutionary success over birds, reptiles, and fish.” The placenta also allows the fetus to eliminate waste and draw the maternal nutrients that allow mammals to develop the large brains that have made us so resourceful. Without viruses, this might never have been possible. Viruses might also be the reason that we split off from chimps five million years ago, since humans developed an effective defense against Pan troglodytes, a retrovirus that affected chimps. At the same time, this defense may have left humans vulnerable to HIV, which chimps can contract without being affected by it. It turns out that one protein either blocks Pan troglodytes or HIV, but never both. If scientists could develop a drug that works the way the protein works in chimps, so as to recognize and neutralize HIV, humans might be able to effectively defend against the virus. Based on this article, I definitely agree that viruses are a driving force in evolution, and after reading it, my entire perception of viruses as changed. Now, instead of thinking of them as a wholly negative force, I can see what a positive effect viruses have the potential to make on our development as a species.
I do think science should “revive” dead viruses because it is clear from this article that there are some significant benefits from doing so. Not only could the revival of dead viruses lead to a cure for retroviruses like HIV, there’s an added benefit of learning more about humans as a species through studying viruses. I do think it is important, however, that scientists exercise caution. Although the article mentions several times that scientists reconstruct viruses so that they can only reproduce once, if something were to go wrong and the virus was released, it could very quickly lead to a pandemic. I would also be wary of so specifically describing how it is that they reassemble these viruses, because the viruses could very easily be used for biological warfare if the means fell into the wrong hands. At this current time, I think the benefits of reviving dead viruses outweigh the risks, but I think scientists definitely have to be careful because if hostile groups were to use previously extinct viruses in war, entire populations could be decimated.