Can a virus 'evolve' ?

[Full of questions]

I am way away from my school days and my scientific knowledge is a bit rusty. I am currently in a debate about if a virus can 'evolve' and I always thought it could. It is true or am I wrong?

 

 

Any answers truly appreciated

[ecoli]

yes they can. It has nucleic acids that can mutate and those changes can be selected for (or against) resulting in different forms.

[Full of questions]

I thought so but was told viruses are intracellular parasites which use host cell machinery to make their components. Apparently a new virus starts as a situation known as “antigenic shift”. The old virus has not evolved as such but a new virus has been created. Most but not all work on viruses has been carried out on influenza.<br style="font-style: italic; background-color: rgb(230, 243, 223); ">When two different strains of influenza infect the same cell concurrently, their protein capsids and lipid envelopes are separated, exposing their RNA, which is then transcribed to mRNA. The host cell then forms new viruses that combine their antigens.

This goes beyond my knowledge but I am not sure this is right

[ecoli]

Be careful with the word 'parasite'. Not all viruses are detrimental to their cellular hosts. There's some energetic costs to replicating DNA that has viral DNA inserted into it, but this is not necessarily actively pathogenic. Interestingly the global virus burden is estimated to be ~ 10^30

[Full of questions]

Yes, that is true...so, is evolve right then? Or is it mutate?

 

Thank you for your answers.

 

I feel I am being swarmed and do not fully see through. Is the argument really there or is it a sneaky way of using words? Is it scientifically correct that a virus can evolve?

[Arete]

Yes, that is true...so, is evolve right then? Or is it mutate?

 

Thank you for your answers.

 

I feel I am being swarmed and do not fully see through. Is the argument really there or is it a sneaky way of using words? Is it scientifically correct that a virus can evolve?

 

Yes it is. The combination of mutation and selection results in the evolution of viruses. They mutate, some mutations confer an advantage to the individuals with the mutation, they become more successful and the new variant sweeps through the population.

 

Here's some papers on influenza virus evolution:

http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1000566

http://www.biomedcentral.com/1741-7007/10/43/

http://cnls.lanl.gov/q-bio/wiki/images/9/91/066_Dreisigmeyer.pdf

[Full of questions]

Yes it is. The combination of mutation and selection results in the evolution of viruses. They mutate, some mutations confer an advantage to the individuals with the mutation, they become more successful and the new variant sweeps through the population.

 

Here's some papers on influenza virus evolution:

http://www.plospatho...al.ppat.1000566

http://www.biomedcen...741-7007/10/43/

http://cnls.lanl.gov...reisigmeyer.pdf

 

That is great, very interesting...thank you !

[CharonY]

Be careful with the word 'parasite'. Not all viruses are detrimental to their cellular hosts. There's some energetic costs to replicating DNA that has viral DNA inserted into it, but this is not necessarily actively pathogenic. Interestingly the global virus burden is estimated to be ~ 10^30

 

Note that parasitism does not refer to pathogenicity. Initially it was based mostly on a trophic relationship, i.e. exploiting the host as a source of nourishment (and usually as habitat), whilst providing no nutrients in exchange. Since then it has been used in different contexts under slightly different definitions. However, from a classic point of view viruses are therefore not parasites (regardlesss whether pathogenic or not).

 

From a molecular biological point of view one could define mobile genetic elements as parasites (of the genome) using non-classical definitions (as it is occasionally done) but most microbiologists would not like that too much.

 

 

 

[magna_nz]

Depends by what you mean by "evolve".

 

RNA Viruses, such as "HIV", are under selective pressures when in the human body (such as the immune system).

 

When RNA Viruses enter a host cell, they use an enzyme called "reverse transcriptase" which turns their RNA into DNA to be inserted into the hosts genome, for later use and for trascription.

 

Since, reverse transcriptase is an error-prone process, the virus, when replicated, has a slightly different genome to the original virus genome.

 

This causes a lot of variants of HIV in the body, and since all of the variants STILL encode a pathogenic virus (rather than code something benign), I guess this could be classified as "evolving".