Zimmer and Viral Evolution

Carl Zimmer has a post responding to some criticism that one of his posts received from the creationist organization, Answers in Genesis. The topic was the evolution of HIV, and Zimmer noted that in studying these types of things, nobody uses creationist assumptions. Follow the link and you can catch up on the argument if you wish.

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Zimmer caught a sentence contained in an Answers in Genesis article.

Viruses can have no evolutionary relationship to any other form, and so whatever may have happened to say, the AIDS virus, has no relevance to the supposed history of truly living organisms in any case.

Actually they do. He also correctly notes that sometimes viruses insert themselves into our genome. He then links to several interesting papers.

 

I'd like to add a couple of links of my own. First, I recently posted about co-speciation of simian foamy viruses and their primate hosts. Also, check out this paper--it's free.

 

Now I know you won't understand everything in it. Some of the technical details I don't fully comprehend either, but here is the upshot:

 

Retroviruses replicate by first inserting their genome into the host DNA (as is the case for HIV). If the viral genome is inserted into a germline cell, the viral genome will be passed on to future generations as part of the host genome (assuming the virus is not too pathogenic). A number of these retroviral genomes (or remnants of them) have been identified in primate (and even more broadly, vertebrate) genomes. Looking at the sequence of these viral remnants and where they have integrated allows scientists to make comparisons among related species. If the concept of common descent is true, you would predict that species that share a common ancestor would share the same viral integration events (ignoring a few potential complications). This turns out to be true and is, in my mind, powerful evidence for common descent. The researchers go a step further and show that certain features of these viruses can be used to support the time of divergance.

 

Viral evolution is a topic I'd like to have a better handle on. It is a difficult topic in some respects because we don't have much to go on in terms of studying ancient viruses. We can, however, make comparisons and those comparisons can tell as much.