I think you're right...
> First, I imagine that such an enzyme would be tailored to match the codon
> usage of the organism of which it is a part, yes? Otherwise, bad things
> might happen. You'll need to solve the degeneracy problem.
Hmmm, yes. I have no idea. My hypothetical was based on the idea
that the enzyme could notice similarities between the reverse-translated
RNA molecule and the DNA molecule exons. This seems a bit far-fetched,
I agree, especially with degeneracies in the codons. This would appear
to make such an enzyme either impossible or really slow.
> Second, what if there are multiple copies of the gene (a not uncommon
> event). The enzyme or, let's be a little more real, multienzyme complex,
> would have to pick the right one? Would this matter in your scenario?
> Let's call our multienzyme complex an antiribosome, since it is
> reverse-translating the protein.
I was thinking 'emosobir' but anti-ribosome is good. :-)
> I think it would be more plausible if you didn't have your antiribosome
> rip apart the extant DNA sequence...it would be better if it just copied
> the relevant portions (the introns) onto its protein-RNA template and then
> reverse transcribed the whole RNA sequence back into the genome, picking a
> spot to ligate the newly made DNA sequence into.
Yes, that might be good, but then the intron information (which might be
important, as I understand it, because it says when and how to construct
the protein, right?) would be lost.
> Thirdly, and least importantly, what sort of practical value would this
> anti-ribosome have...in terms of survival value, I mean. :-)
This is an easy question to answer, I think: If there were common reverse
translation between protein and DNA, then effectively the DNA would have
information about how well its proteins were faring in the outside world.
That is, if protein X were doing better than Y, then pretty soon the DNA
would code for X instead of Y, allowing Larmackian evolution to take
place. Whether this would be good in the long run is hard to figure, I
think, but it sure seems like it would be good in the short run, which
is all that matters at first. That is, the DNA would adjust to its
environment in real time, instead of through successive generations of
mutation/selection. Even if reverse translation happened piecemeal,
it would help, it seems. So reverse translation I think would be a
good thing for the organism, although the faster response time would
certainly alter the long-term situation. I'm not sure how to make that
prediction, though.
-Greg
> Gene
>
> ____________________________________________________________
> Gene D. Godbold, Ph.D. Lab: 804 924-5167
> Research Associate Desk: 804 243-2764
> Div. Infectious Disease Home: 804 973-6913
> Dept. Internal Medicine Fax: 804 924-7500
> MR4 Bldg, Room 2115 email: anselm@virginia.edu
> 300 Park Place
> Charlottesville, VA 22908
> """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
>
>