The discoveries associated with the role viruses play in evolution, as presented in this article by Michael Specter, follow the laws of evolution presented by Darwin, yet from this extremely new and rather surprising perspective. It turns out that viruses have significantly influenced the changes that occur in organisms over time. Specter quotes professor of viral oncology, Robert Weiss, saying, “ [Darwin] might be surprised to learn that humans are descended from viruses as well as from apes.”
Darwin focused largely on the role organisms’ environments played in their evolution. The viruses that are thought to affect our evolution are “endogenous”; they are considered a part of us. The influence of something so deeply implanted within us (within our very genome) on our evolution contrasts the influence of the environment, something wholly external. That influence of something that “lives” within us would be surprising to Darwin since it is less obviously an environmental effect than weather or geological features Darwin attributed to influencing an organism’s evolution.
While the entire article contained surprising and fascinating information, I was most surprised at the last page of Specter’s article, where the work of Luis P. Villarreal’s work is discussed. He explains that “without an effective AIDS vaccine, nearly the entire population of Africa will perish”, but the humans left behind will be “ ‘distinct’ from those whom H.I.V. makes sick.” The article states that this process would take tens of thousands of years resulting in “a new species of human.” I have known since elementary school, in some capacity, that the humans of today will eventually branch off into other species but it is incredible to actually see some hypothesis for how those humans may differ from us in the future. This information ties together the whole of the article, all of the science explained and the “utilitarian” value of paleovirology. It leaves a fascinating prediction for the future.
In the article, scientist Thierry Heidmann states “…The Phoenix virus [an extinct virus he helped reassemble] sheds light on how H.I.V. operates…more than that on how we operate, and how we evolved.” Heidmann and other scientists interviewed throughout the article reference the role viruses have played in the formation of placenta in mammals in the history of our evolution. When scanning baboon placentas the scientists saw “ retroviruses on a layer of tissue known as the syncytium, which forms the principal barrier between mother and fetus.” Those retroviruses allow the cells of the placenta to “fuse” similarly to how a virus would “latch onto the cells they infect.” The article also mentions that without placenta mammals could not remain in the womb as long as they do, gaining nutrients that allow them to have large brains necessary for their “versatility.”
Additionally, the defense we have built against certain viruses throughout the years has lent itself to our survival and the survival of other organisms such as chimpanzees who were once exposed to a virus similar to AIDS but cannot get sick from it. Chimp genomes contain copies of the virus PtERV which defends them from AIDS. Humans genomes do not contain PtERV, thus we get sick from AIDS and as with Villarreal’s example with what may happen in Africa, may affect our evolution. Similar occurrences are believed to have completely occurred in the past, contributing to evolutionary changes.
I believe that more research will have to be done to understand the extent to which this “junk DNA” has influenced our species but this article still changes my perceptions of viruses a great deal. I had seen viruses as something that will certainly die off over time, but this makes me realize it takes a lot of time to eradicate a virus, sometimes it can not be completely destroyed at all. I also viewed viruses as something that almost completely disappeared once someone healed from whatever illness the virus caused, besides some form of resistance. I now know that resistance can last thousands of years.
From reading Specter’s article, it is clear that “reviving” dead viruses can give scientists information about curing illness that is hard to come by otherwise. With tight control, I believe the potential good that can be done with reviving dead viruses outweighs any possibility for ‘bad’ outcomes. As Heidmann states, “The knowledge will help us treat terrible diseases.” Studying viruses allows us to understand more of evolution, which could prove helpful outside of curing illnesses. Reviving dead viruses has helped scientists identify happenings of the past, like when a lentivirus was active or when chimps were building resistance against AIDS. Fear of the unknown should not keep us from knowing more about ourselves. There will always be somebody or something threatening our ability to thrive; I believe the more we know, the better we can defend ourselves.