Microbiology
cartoon of animal viruses

Viruses and how they Survive



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"Viruses and how they Survive"
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A Quasispecies model of sequence evolution is necessary for scientists as a labeling tool for organisms with particular replicating habits.  This method is a hangover from Darwinian science and is in direct opposite from species. Species are usually true to their inheritance and mutate slower.

Into this group are Viruses and other related organisms of dubious character that have been known for at least a hundred years, and even longer, but in the last twenty years RNA and DNA studies and information gathering has changed the picture of medicine considerably. Much has been learned. Methods of detection now most always concern the idea of viral groups as being quasi-species.The method by which they survive, moving from host to host in order to replicate, mutating while moving on, is more of prolonged process, but model now used in virus studies. Although only in its rudimentary stages, there's still much work to be done.And too there's evidence that this model need to be improved upon, or changed. 

How do these elusive toxic organisms  evolve and why is it necessary to have a model of sequence evolution? It's not clearly known how they evolve but in order to learn more about this process scientist must have a working model that's known to all and one that's consistent. When deviants appear form this model then the know there must be changes taking place within particular groups of these quasi species. 

Specifically, how to explore the genetic makeup of viruses, the quasi-species, or the many mutations they undergo as they move from host to victim to host and in particular describing the model by which virologist use as guidelines is the theme of this article. It is an ongoing thing, as each year brings more information on how they cause diseases, and what can be done to stop these vicious attacks.

Viruses have been known for at least a hundred years, and even longer, but in the last twenty years RNA and DNA studies and information gathering concerning these have changed the picture considerably.  Methods of detection now most always concern the idea of viral groups as being quasi-species and therefore being nearly the same as others, but not quite.

The method by which they survive, moving from host to host in order to replicate, mutating while moving on, is more of a prolonged process, but is the model now used in virus studies. Although, even here, it’s only in its rudimentary stages, there's still much work to be done.

And too, as if to borrow a method of study from the quasi-species of viruses themselves, the model favored today is one that sequences itself as better ways and means of detecting the habits of these illusive organisms, or at least the virologist's conception of them. That idea has been borrowed from a general explanation of the original quasi-species model "representing a large set of replicating nucleotide sequences . . . each with an associated fitness, a constant value that corresponds to the reproductive potential of that variant. . . ."

In other words, the model used most often proceeds step by step and assumptions are made that at this stage everything is equal and the reproductive cycle of the virus proceeds along these lines. Assumptions of course could be wrong, but for the time assumptions are necessary if any conclusions are to be forthcoming.

The sequence that makes the best fit is called the master sequence, or the leader. If, however, it does not persist in keeping its fitness level - labeled as a0 - moves beyond a1/Q, it will no longer be useful, will be extinct, and the next "mutant tail" will take over as the master sequence.

A word of explanation: The sequence for clarity and ease of understanding progresses 0, 1, and Q represents the amount of errors during mutation. Errors mean differences from the previous characteristics of the virus.  The equation for a true to form master sequence is a0>a1/Q and anything beyond that will render the equation false and will cause it to become extinct. 

To fully understand the process and to put it into perspective is to see viruses in their attempt to survive as survival of the fittest, and anything not contributory is discarded. Controversy surround much of what is know about these scientific theories and possibilities. It is not unlike larger organisms made of multitudes of cells that likewise clamor for survival such as the human body and its adaptive mechanisms, as an example. There are differences: The viruses are phagocytes, they must live off living matter, and the human host is one type of their adaptive sequence of life style. 

The scenario is such as this: It's the leader of the pack theory reduced down to its smallest measure. As explained in the research text, if the master sequence's average is lower than an existing mutation with a higher average of fitness to the overall model, then it will be dominant. And again, referring to the virus's model of the human body where its aim is toward balance of all of its parts, and to the degree that is accomplished, is the distinction of being healthy or unhealthy.

Healthy means different things when viewed through the eyes or senses of viruses, as when viewed by a human organism. The tug of war between illness and wellness goes on. In theory at least, the healthier a virus sequence is, the less healthy the human host it occupies will be.

Originally, quasi-sequence thinking was applied to the study of ribonucleic acid (RNA) studies; it further led to RNA Viruses and has been used as a model. RNA is defined as a linear polymer of nucleotides found in the cytoplasm of a cell. Its microsmomes contain genetic material from DNA and RNA transports it to other cells. DNA, deoxyribonucleic acid, is likewise a long strand of genetic material shaped like a double helix and is the map of genetic information. RNA is the transporter of this information. This theory is now in question. 

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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://www.virology.ws/2009/05/11/the-quasispecies-concept/
  • InfoBoxCallToAction ActionArrowhttp://www.ncbi.nim.nih.gov/pmc/articles/PMC1208876/
  • InfoBoxCallToAction ActionArrowhttp://academic.research.microsoft.com/Paper/14264880.aspx