About viruses.. General info?

Question

All of a sudden, I am fascinated by viruses. Does anyone have any book recommendations that might answer some of the following questions..

Did viruses evolve before or after bacteria?

Are there beneficial viruses? Like a virus that would "help" the host?

Can viruses be manufactured?

As far as biological classification goes, how are they classified? I know they aren't considered living.

etc...

Thanks! I appreciate it. I'm so intrigued, I need to know more.

Answer 1

Did viruses evolve before or after bacteria?
We really don't know, but probably both. There are two schoools of thought on the origin of viruses. One suggests that viruses degenerated from cells, becoming totally dependent on their hosts. This is definitely true for many viruses, particularly DNA viruses. The other theory suggests that viruses, in particular RNA viruses, were the first form of life.

Are there beneficial viruses? Like a virus that would "help" the host?
Yes. There are viruses that infect fungi that live in plants around hotsprings. Without the viruses, the fungi and the plant die from the heat (Science. 2007 Jan 26;315(5811):513-5). There are probably many others, it's just that we often don't bother to study viruses unless they harm us or something we care about.

Can viruses be manufactured?
No, not really. There was a well publicized event where researchers were able to recreate a virus using short fragments of synthesized DNA, but this is very difficult and requires extensive knowledge. There is no way to generate a virus "from scratch" without knowing it's entire sequence.

As far as biological classification goes, how are they classified? I know they aren't considered living.
Most virologists consider them to be alive. They aren't classifed into their own kingdom, but perhaps someday soon they will be. Look below to see how the Tree of Life project treats them.

Answer 2

I'm not sure about books, but I can try to answer your questions.

>Did viruses evolve before or after bacteria?

Bacteria I'm not sure. However viruses certainly evolved after cells, because viruses require cells to survive. The question then is whether the first cells were considered bacteria or not.

>Are there beneficial viruses? Like a virus that would "help" the host?

This is theoretically possible, but so far I haven't heard of any naturally occuring virus that does this.

>Can viruses be manufactured?

Depends what you mean by 'manufactured'. If you got a culture of cells and released a few viruses, you could very easily make a lot of viruses. However if you want to do it using just simple chemicals rather than living cells I don't think people can do that on a very large scale yet.

>As far as biological classification goes, how are they classified? I know they aren't considered living.

Actually, last I heard scientists were still debating whether or not they were alive. Personally I would consider them alive, because even though they are often not active themselves, they are still successful enough at reproducing and evolving that they can hardly be considered dead.

Answer 3

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Answer 4

As of last semester it was still being argued whether viruses are considered living or not. You may want to read into a microbiology textbook....or if very interested take a class on microbiology because there you may get to grow your own specimens and stain them, etc. I didn't think Microbiology was going to be too much fun but I loved it and the lab was an excellent opportunity to learn! I would highly recommend Microbiology to anybody who likes learning about diseases...but even more than that find a class that has a lab!