In the video sent by my teacher on viruses, the example he used for lysogenic viruses was a bacteriophage infecting a bacteria. When he was describing how the genetic material was incorporated into the host cell's genetic material, he said something along the lines of:

Now the genetic material is incorporated into the cell's chromosome.

My question is, did he describe it as one main chromosome because that was the example being used? Or do lysogenic viruses only infect bacteria?

I guess a better way of phrasing this would be, are bacteriophages the only type of lysogenic viruses?




1 Answer 1


Bacteriophages are the only viruses where this phenomenon is called lytic and lysogenic cycle. There is a similiar phenomenon in humans (and other mammals as well) which is called "endogenous retrovirus" and is pretty common. For humans, there are estimations that something between 5 and 8% of the human genome are made of endogeneous retroviruses. See these two references:

Otherwise I can recommend reading the article on "Endogeneous retroviruses" in the Wikipedia, it is pretty extensive and has a lot of references.

  • $\begingroup$ This is really a question of semantics. Yes there are endogenous viruses in eukaryotic cells, but is the term lysogeny used to describe this situation in practice? (I don't think it is.) $\endgroup$
    – Alan Boyd
    Commented Mar 10, 2014 at 13:09
  • $\begingroup$ Now that you ask direct, no I don't think so. I think this was discovered with the Phage Lambda in bacteria. I will edit the answer. $\endgroup$
    – Chris
    Commented Mar 10, 2014 at 13:25
  • $\begingroup$ I'm confused -- the terms 'lytic' and 'lysogenic' don't apply if the host cell isn't a bacteria? $\endgroup$
    – evamvid
    Commented Mar 10, 2014 at 17:29
  • 1
    $\begingroup$ Obviously it is not used outside the context of phage-bacteria. Although endogenous viruses in our genome are more or less the same. $\endgroup$
    – Chris
    Commented Mar 10, 2014 at 17:33

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