As someone who seems to constantly be sick, I must say that I am terrified of viruses. The last thing I want is to pick up a virus that is going around school, and be down for the count again! However, I had no idea before reading “Darwin’s Surprise”, that viruses, although they can cause incredible amounts of harm, aren’t pure evil. I was shocked to learn that not only are extinct retroviruses incorporated into our human genome, but as a result, they have helped us to evolve into the complex species we are today. Furthermore, there is the potential for viruses that haunt the human population today, such as HIV, to become extinct eventually, like endogenous retroviruses (the viruses embedded in DNA).
My first shock while reading the article occurred when I learned that “It takes less than two percent of our genome to create all the proteins necessary for us to live. Eight percent, however, is composed of broken and disabled retroviruses, which, millions of years ago managed to embed themselves in the DNA of our ancestors” (64). Initially, I was petrified at the thought of 8% of my DNA being composed of viruses with the potential to make me, and others, sick. Luckily, the author clarified that none of the endogenous retroviruses are able to function and actually make someone sick. However, as I continued to read, and learned that the retroviruses can be brought back to life, the fear began to return. When in the wrong hands, the return of these viruses could harm millions of people. I can’t help but think about the fact that the viruses went extinct in the first place for a reason. Nevertheless, I am fascinated by the positive impact bringing the viruses back to life, for research purposes, could have.
Bringing the retroviruses back to life would allow researchers to better understand a species’s evolutionary past, as well allow them to better understand the present and future of medical complexities, such as HIV. One discovery regarding endogenous retroviruses is their involvement in the development of the placenta. Without the development of the placenta, mammals would not have been able to develop the large brains that make mammals so versatile, since eggs can’t draw maternal nutrients. Therefore, viruses have helped species to become more complex and intelligent. Another discovery regarding endogenous retroviruses revolves around HIV and the endogenous retrovirus PtERV. By bringing PtERV back to life, scientists were able to discover that the evolutionary process that protects humans from PtERV may be why we are vulnerable to HIV. They also learned that HIV could one day become endogenous, meaning it would become extinct and no longer pose a threat to the human population.
It is clear that endogenous retroviruses hold clues to our evolutionary history and future. Those clues shed light on the beneficial effects viruses have had on life on Earth. Learning about these effects, and the potential positive effects viruses could have in the future, has helped me realize that although I detest viruses for making me sick, they aren’t completely terrible after all.