Don’t Judge a Virus by its Capsid

Darwin’s Surprise addresses evolutionary patterns that Darwin could not possibly have imagined. Though he had a good understanding of evolution, Darwin did not know anything about the structure of DNA or how it perpetuated traits from generation to generation. The article discusses the importance of DNA and how it has changed to reflect who we are today, and how some of these changes are the result of ancient viral DNA incorporated into the human genome. Natural Selection emphasizes that the fittest will live to reproduce and pass on their genes, so the immediate reaction to an organism being infected by a virus is the assumption that it is weak and will die out. However, the article postulates that retroviruses that were incorporated into our genome have likely helped us to evolve into the species we are today, in some cases providing immunity to other infectious agents.

The most outrageous concept—from Darwin’s point of view—is the revival of extinct viruses by piecing together common sequences from a certain species. This reversal of time seems to go against the idea that natural selection will cause the weak to die out permanently, but really it strengthens the connection between us and our ancestors by revealing past exposures and uncovering the evolution of viruses. By better understanding the development of viruses, we can more accurately predict how viruses will change and therefore create effective vaccines.

The article suggests the viruses play a much bigger role in evolution than just killing off the weak. Retrovirus sequences have been perpetuated for thousands of years. Though sometimes referred to as “junk DNA,” these sequences must serve some purpose because they are still present. Studying the history of viruses also reveals deep evolutionary connections. One population’s exposure to a virus and subsequent incorporation of the viral DNA may have caused a divergence, leading to a new species. This article offered a different perspective on viruses, highlighting that while they can be problematic, they can also be beneficial.

The most surprising part about this article was the alternative approach that scientists are taking to fight HIV. Instead of preventing the viruses from reproducing altogether, they capitalize on the high mutation rate and force the virus to replicate faster, hoping that the frequent mistakes in replication will add up so that the virus is no longer harmful. While its easy to understand that some might have reservations about the safety of such research, the revival of ancient viruses is an important pursuit because it helps understand how retroviruses, like HIV, work. Knowing this, we can hope to create a vaccine, or possibly force the virus into extinction.

However, given all that we know about evolution and resistance, is it possible that the more we understand and fight viruses, the more we encourage them to evolve and the harder they will be to control? Are we just perpetuating a cycle? Solving a puzzle, only to find another layer more complex than the last?

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