Is anyone knowledgable about DNA and retroviruses

People enjoy and accept the very light genetic theory of the X-Men comics. As I recall, perhaps incorrectly, the vampirism in the Blade movies that starred Wesley Snipes was a virus of some sort.

Even though we've mapped the human genome, there's still enough mystery to it that I don't see why that wouldn't work inside a good story.

BUT! I'm slightly above layman in terms of genetics knowledge.

I agree with Rob, but I have never taken any courses in genetics. One thing that I think of now and then is doing something with some of that "non-coding" DNA. What might be tucked in there ready to start coding when stimulated by something?

My husband, a PhD in that field, says, "Sure."

Tinman said:

Hi. I want one of the characters in a novel to make a passing comment, something to the effect of: "It might come from a dead end in our evolutionary chain, an ancestral segment of DNA reactivated by the virus." Does this make any sense? Thanks!

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I wouldn't use the "dead end in our evolutionary chain" part unless the virus has gotten to the preserved DNA of an ancestor of Homo sapiens. As for a virus reactivating a previously unused section of our own DNA, sure. No problem believing that.

The great L. Sprague de Camp used this idea in the story "Hyperpilosity", in which a version of the flu switched on the gene that causes people to grow body hair, so that everyone developed a full fur coat.

Makes sense to me. The human genome contains lots of retroviral DNA segments. That's another avenue you could explore.

I'm not sure what you mean by "reactivated" in this case. Usually, a viral infection means that it injects its own RNA/DNA into the host and forces the host's cells to begin producing viruses. In some cases, viruses can take up external genetic material (which is useful in research) and can actually take up host genetic material as well (and begin to express the DNA). So in this case, the virus could express the "ancestral DNA", but I'm not sure about it being able to get the human to express the ancestral DNA since viruses usually don't modify the host genome. That being said, there's a lot of weird stuff out there, so it's not completely infeasible. Maybe the virus could potentially, in some weird way, cause alternative splicing to occur and thus reactivate a previously spliced out sequence of DNA.

I wouldn't use "dead end" or "evolutionary chain", since one of the main ideas of evolutionary theory is that there is no end goal, just adaptations. "Dead end" implies a failure in evolution and "chain" doesn't make sense. Instead of "ancestral segment", use junk DNA. Even if it doesn't sound very scientific, that's the term that's used the most. About 90% of the human genome is junk DNA, and therefore does not actively code for protein creation. I think that number recently went down, but that's what I remember.

It's important to use the right scientific terms, since scientists are extremely precise in their daily conversation, especially about their field of study.

It is completely possible for a segment of DNA to be changed/added/reactivated. There's a two ways to go about that realistically.
1. Inserting a segment of DNA on purpose is possible via viruses or bacteria, and is called gene therapy. It's currently the subject of a lot of research and could be a really useful plot device in fiction. Try this website: http://learn.genetics.utah.edu/content/genetherapy/gttools/ It's a little long, but really informative.
2. Mutation of DNA happens everyday in all humans. It happens when a mistake is made when copying DNA. The mutations that really matter are those in egg or sperm cells, since those affect the entire body of the future offspring. Most mutations are harmless and barely noticeable, some are harmful (think genetic disorders), and a very small percentage are useful. These few useful mutations are what cause evolution. These are accidents, but could be used on purpose if you had an mad scientist character or something. (This is what's used in X-Men).

If this is unclear or you wanted more details, let me know!

Source: Me, a sophomore double majoring in biochemistry and biology

I'm not sure about the specific terms, "Trigger," is one that could be used but virus can and do bring out parts of our DNA. There are theories that West Nile virus can trigger myasthenia gravis in people with a genetic predisposition. Psoriasis can be triggered by pneumonia, which is a virus, or Strep Throat, which is a bacteria. So, what you're saying is plausible, and I think works as a story device. Then you get into the whole conversation about epigenetics, and methyl groups effecting what parts of our DNA is activated.

Tinman said:

It doesn't really matter to the story; a layman is making a guess at what could be causing a problem. I just didn't want him sounding like a complete idiot. But, for clarity's sake, is the problem more with his choice of words: reactivated instead of expressing? Just curious. Thanks!!

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If that's the case I'd just make him have psoriasis that was triggered by pneumonia. It would give him a plausible reason for suspecting this and an easy way of explaining it. Something along the lines of, "I didn't have psoriasis until I got sick with pneumonia, and now I have it. Maybe the virus works like that."

A little late to the thread but I want to agree that this sounds totally reasonable to me, except I would take out the "evolutionary dead end" bit. I would also talk about the "reactivated" segment of DNA as being expressed as opposed to repressed.

Oooh, I know, you can say that it's a pseudogene.