This article is appropriately named “Darwin’s Surprise” because of the likely reaction he would have had to the findings of Heidmann, Temin, and the like; “humans are descended from viruses as well as from apes”. Endogenous viruses are an integral part of our genome, with 8% of our genomes being composed of fossilized or otherwise disabled retroviruses. While these genomes are still considered “junk” DNA, they are very important in unraveling and understanding the evolution of humans. Darwin probably never would have imagined that tiny, lifeless molecules that wreaked havoc on prehistoric humanoids were actually a big factor in our evolution, with some scientists today speculating that, without the viruses, we would not have evolved the same way.
I had no idea we were comprised of bits and pieces of past retroviruses that had plagued our ancestors. I knew some viruses embedded themselves in host DNA, but I didn’t know ancient ones were present across the human race. Also, the fact that these bits of retroviruses could potentially have positive effects on humans seems like an oxymoron, but the article was fascinating in that it explained possible theories for this as well. I knew that scientists could reconstruct past viruses from outbreaks (like the article mentioned), but I wasn’t quite sure of the exact method.
The article says that, as retroviruses became a part of the genome in the germline cells of our ancestors, they were passed along to the rest of the human race and were eventually disabled, either through immune response or too many mutations that render it incapable of carrying out its function. Some of these bits and pieces still carry out minimal function, just with no effects to the host whatsoever. However, these endogenous retrovirus bits can have effects on other viruses we’re exposed to, protecting us from them. Some of the scientists mentioned, including Heidmann, believed that humans would not have evolved the same way without the help of these viruses; i.e., the development of the placenta seemed to be a direct result of these endogenous viruses. After reading this article, I have a whole new perspective. Say ‘virus’, and the first thing many people think of is illness and death, not human genes and AIDS vaccine research. The amount of complexity one little molecule has and its effect on the human race is amazing, and the fact that endogenous retroviruses may one day lead to finding a cure for AIDS is phenomenal.
I think the idea of reviving dead viruses is more helpful than scary. I have seen my fair share of sci-fi movies/shows where a synthesized virus used in biochemical warfare kills off half the planet (or makes them into zombies). While this is a far stretch, there is a bit of reality, as seen with the State University of New York at Stony Brook students who made a polio virus “to prove it could be done”. However, the grand majority of revivals are being done in labs with strict ethics and one-generation termination sequences to prevent anything from going awry. These controlled experiments are what brought about the discoveries about how some endogenous viruses act as beacons to HIV infected cells, allowing them to be terminated. The amount of research and prevention of further retrovirus outbreaks that these ‘revivals’ are responsible for far outweigh any other concerns.