Wednesday, October 04, 2006

The Logic of Viral Pathways to Life

Finding plausible pathways to life has been an effort plauged by dead ends and a shortage of useful supporting data. Frustration spawns unsound theoretical approaches. An example is the belief that since viruses are less complex than cellular organisms they would have been cellular precursors.

Viruses do have much smaller genomes than cellular organisms and are less complex yet they also contain nucleic acids with encoding capacities and have the capability to hijack the cellular machinery of a suitable host in order to replicate. Viruses utilize cellular transcriptional mechanisms to effect their replication. Although relatively small, viral genomes contain a good deal of sequence specificity. The specificity is related to the replication function and is clearly adapted to the mechanisms of their cellular hosts. Enzymes like integrase and reverse transcriptase illustrate the fit between viruses and cells. To put it in Darwinian terms the selective value of viral genes is host dependent.

That should give pause to thinking evolutionists intent on believing that simpler equates to an evolutionary precursor. If natural selection is invoked as an explanatory device then it would favor viral genomes most efficiently adapted to their parasitic functions and the specific host organisms serving the parastic role.

Of course an alternative viral theory of origins exists. Rather than having been precursors to cells, their origin could owe itself to a degenerative process that involved cells as the initial source of what later became viruses. However whether degenerative or precursor, the logical link between cells and viruses is clear. The functions of viral genomes are explained by their interactions with specific cellular hosts. Clear too is the selective value of viral genomes; that is there is clarity for those whose view is not determined by a precommitment to an origins paradigm devoid of purpose and intelligent direction.

1 Comments:

At 11:43 AM, Blogger Doug said...

Great article. MikeGene had written an article called "Extreme Evolution: A View From Three Perspectives" (http://www.idthink.net/biot/ext/index.html)

In it he addresses mycoplasmas, microsporidia, nanoarchaeum equitans (and mitochondria) mentioning about how in each case researchers were assuming, based off of their diminutive genome sizes, that these organisms were primative. In each case these organism's (as well as mitochondria) diminutive genome was derived, not primative. At the end of the article MikeGene speculates "....we have good reason to predict that viruses, rather than reflecting some primitive state, represent the extreme end of this far-reaching, evolutionary trend." That trend being a simple organism, assumed to be a primative precursor, that is actually derived from a more complex state.

 

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