Darwin’s Surprise – Viruses & Human Evolution

The article Darwin’s Surprise by Michael Specter explores the work of scientists and researchers who are looking to find the connections between endogenous retroviruses and evolution. A retrovirus is a virus that can transcribe its RNA genome into DNA within a host cell, and endogenous means the viral incorporated into the genome of the host’s species.

According to the article, what Darwin would find most surprising and elating is the further evidence for his theory of evolution. Near identical fragments of deactivated endogenous retrovirus genetic information have been found in the DNA of humans and our primate cousins, descendants of a common ancestor. These viruses act as “breadcrumbs,” allowing scientists to track the history of viral infections. They would not be present in the genome of a number of related species if they were not advantageous, and if nature had not selected for them.

What I found most surprising about the article is that these viruses that become part of our genome can actually benefit the evolution of our species. While it is rare, some of these viruses produce proteins that keep other viruses from infecting the host, viruses that may be even more harmful. I think health news and media focuses so much on riding ourselves of certain viruses and disease that may be beneficial in the long run.

In terms of evolution, the article suggests that “we have been in an evolutionary arms race with viruses for at least one hundred years.” After being infected by a virus the host adapts. The viruses then mutate and the cycle repeats itself. Viruses have lead to the development of placenta’s in mammals, and helped humans fight off viruses (i.e. PtERV) while remaining susceptible to others (H.I.V.).

After reading this article, I have definitely come to appreciate the power viruses have over the course of evolution and better understood the benefits of studying them. As long as they are studied in a controlled, legal and ethical environment, I do not think there are many reasons scientists shouldn’t revive old viruses. Studying ancestral viruses may be the keep to preventing mass viral epidemics in the human population, as well as in endangered species of animals.

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One Response to Darwin’s Surprise – Viruses & Human Evolution

  1. KatieD says:

    I agree with the media oversimplifying the role of viruses in the human species. Sure, viruses do infect and kill a lot of people, but they also have many benefits in conjunction with these costs — benefits that are often overlooked in the sea of mass hysteria surrounding the dangers of viruses. The media goes wild when there are viral outbreaks — news stories cover in great detail the scary magnitude of epidemics, including H.I.V./AIDS, but they never seem to have coverage of the benefits these types of diseases can have on human evolution. Like Salvador mentioned, viruses not only infect and kill, but, in the long run, they help to protect from even deadlier diseases; the fittest survive, and they are better adapted to deal with any new challenges that may come. If we want to fully understand where we came from, we have to look at viruses holistically — viruses may have a negative short-term impact, but the long-term is pretty positive.

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