“If Charles Darwin reappeared today, he might be surprised to learn that humans are descended from viruses as well from apes,” said Weiss. Darwin’s work is popular for providing the mechanism of evolution – natural selection – and for coining the idea of a common ancestor. The only way that humans, from around the world, can have the exact retroviral DNA found in other species is by inheriting it from a common ancestor. Bieniasz and his team took ten versions of the Phoenix virus from the human genome and sequenced them. He found that they were nearly identical to each other. He was able to piece together the virus, making it fully functioning. Let’s just take a step back from that. He took ten genetically similar dead retroviruses, and successfully pieced it together. Furthermore, a whopping ten percent of our DNA is made up of retroviruses, leading scientists to believe that they played a major role in our evolution. It’s clear that their impact on humans have been server because of our defense system against them.
To me, this was very surprising, probably for the same reason it surprised Darwin. Viruses aren’t considered living by definition to biologists, and yet it’s hypothesized that we have evolved from them? They are single celled, and are composed of nothing more than protein and DNA. But, the article explains that they may have protected us from viruses much more severe. They can defend us from infections by viruses with similar genetic structures, but it would be nice not to have either parasitic organisms taking over our cells.
To expand on a tangent, I would like to return to Bieniasz’s work because it’s not the first time I’ve heard of something like this. I watched a TED talk about de-extinction, and it encompassed a very similar process where they would take the tissues of an extinct animal, combine it with an organism that has a very similar genetic sequence (to fill the holes). Then they implanted the combined DNA into the organism’s embryo, and when the fetus came to term, the extinct organism was born. It lived, but only for a few minutes. It was amazing. Just the fact that scientists have reached a point where they could revive extinct organisms!! Here is a link to the talk, if you’re interested:http://www.ted.com/talks/stewart_brand_the_dawn_of_de_extinction_are_you_ready.html
Going back to how viruses impacted our evolution, it surprisingly makes a lot of sense to me. When I was younger, and learning about the differences between mammals and reptiles, I always wondered why platypuses laid eggs despite the fact that they were mammals. But in biology, there are always exceptions, right? Now, I finally have my answer. Though they are the exception, we evolved from them. They were never the organisms that branched off from live births, but us who branched off from them. The development of the placenta allowed for embryos to grow within the mother to have access to nourishment, rather than growing in an egg, where it could transform into a parasite. Heidmann brings this point home by saying, “It is quite possible that, without them, human beings would still be laying eggs.”
That point alone completely changes my perspective on viruses. They have influenced our evolution for the better. They made us stronger to our environment. Though they have helped us in the past, I think it’s foolish to revive dead viruses. They are dead for a reason; natural selection has already made that clear. If they ever need to come back, nature will take its course and allow for that to happen. But for science to intervene is risky, dangerous, and crazy. Viruses are parasitic; they hack into our cell’s hardware and shut us down. Though I can understand why scientists want to bring back dead viruses to learn more about different organisms and species, I’m against it.