Darwin’s Surprise

Specter’s article was interesting because he challenged the negative connotations of the word virus. I was really surprised that viruses have actually been responsible for much of human evolution. The quote in the last line, “‘Viruses may well be the unseen creator that most likely did contribute to making us human,’” was particularly striking. Specter mentions that in 2003 researchers discovered that our bodies contain fragments of the genetic code of retroviruses. Most of these endogenous retroviruses that have left nonfunctional genes in our DNA (that has been passed down from our ancestors) no longer have any effect on humans. Essentially, these viruses are extinct and their remnants remain in our genome. I was really surprised that researchers have been able to resurrect some of these ancient viruses and that such a feat might prove to be instrumental to discovering how to fend off current deadly viruses, such as HIV.
While the act of reconstructing an ancient virus is astonishing enough in itself, even more astonishing is all the opportunities that can come from this accomplishment. For example, researchers were able to determine that the reason HIV does not affect chimpanzees, our closest relatives, is due to the copies of the PtERV retrovirus they contain. Humans have a gene that creates a protein that destroys PtERV, while the rhesus monkey contains a single gene that protects against HIV. Through the reconstruction of the PtERV retrovirus, researchers are hopeful that an effective drug could be developed against HIV if they can figure out how to get our gene to act like that of the rhesus monkey. I did not think that the study of ancient viruses would be so helpful to figuring out how to stop the viruses that are prevalent today. Although it may be long in the future before tangible defense can be made against viruses like HIV, I definitely think that the study of past retroviruses will lead us in the right direction.
In addition, research has revealed connections between some human mechanisms and that of retroviruses. I thought it was interesting that cell fusion is an important characteristic of both the mammalian placenta and endogenous retroviruses. The protein responsible for cell fusion in the placenta even uses the same mechanisms retroviruses us to attach to host cells. Clearly, the history of retroviruses and humans are intertwined. Viruses are always evolving rapidly, more rapidly than we can comprehend. However, we are beginning to discover that their evolution is closely linked to ours and perhaps are even responsible for some of our advantageous traits.

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2 Responses to Darwin’s Surprise

  1. AzizeA says:

    I actually disagree with the idea that studying ancient viruses would not be immediately helpful in combating viruses today. The purpose of looking at older viruses would be to explore how they evolved over time and how we evolved to combat them. As an example the article mentions that “‘It’s very likely that we have been under threat from retroviruses many times throughout human history. It is eminently possible that this is not the first time we have been colonized by a virus very much like H.I.V.’”. If this is true we can look back at these viruses and see how we fought them off before and put that to practical use in creating vaccines or other ways of getting ride of viral infections like H.I.V.. At the very least it would allow scientists to have a better understanding of lentivirus evolution, which could be used in creating H.I.V. cures that center around speeding up the evolution of the virus to the point it has so many errors it is no longer dangerous to the human body.

  2. kristentk says:

    I was also surprised with how they were able to figure out why HIV is able to infect humans but not chimpanzees. I did not expect that a greater defense mechanisms against one virus made us more vulnerable to another one. It reminds me of how not being heterozygous for sickle cell disease makes someone more vulnerable to die from malaria.

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