On 8 Oct 1997, Ed Rybicki wrote:
> > From: Leonard Pattenden <ddlpatte at mailbox.uq.edu.au>
> > Subject: Re: viruses, evolution, and net traffic
>> > My understanding of Viral evolution - as a protein chemist working in HIV
> > - is that viruses are escaped genes. Thus - for example - in many
> > retroviruses we see the aspartyl protease which cleaves the GAG-POL
> polyprotein
> ..
> > smaller homodimeric protease we see today. The implication of my beliefs
> > to your suggestions, is that propensities for particular viral types must
> > reflect the availability of the machinery within the cell. Ie if a plant
> > cell can produce reverse transcriptase which could be incorporated
> > somehow into a virus, then the feasability of an RNA virus is
>> Okayeeee...first problem: not all viruses can be boxed with
> retroviruses as "escaped genes", at least, not as RECENTLY escaped
> genes.
Fair enough, but the point is still valid, retroviruses was an example.
In fact, there are no classical retroviruses (except maybe
> some retrotransposons which turn out to be infectious) in plants;
> only pararetroviruses of presumably ancient lineages (in that ALL
> retroviruses look MUCH more like each other than badna- and
> caulimoviruses look like each other).
Interesting, but the arguement still stands.
>> Second problem: you will find some mammal-infecting viruses in the
> same superfamilies (based on polymerase homologies) as plant
> viruses...seeing as land plants and mammals diverged some 10exp9
> years ago...see what I mean?
Yes. I understand your point. Quite frankly, how much faith would you
hold to polymerase homology in light of the size of a viral genome and the
period of time you have put forward for divergence?
Len...
