Re: DNA, RNA and Protein questions

On Mar 18, 7:13 pm, Bill <spintro...@xxxxxxxxxxx> wrote:
On Mar 18, 9:20 pm, hersheyh <hershe...@xxxxxxxxx> wrote:



On Mar 18, 3:10 pm, Bill <spintro...@xxxxxxxxxxx> wrote:
That doesn't make sence.

So

Fish once dominated, amphibians came and fish survived.
Reptiles once dominated, mamals & birds came and reptiles survived
Bacteria once dominated, archaea & eucaryotes came and bacteria
survived.
etc, etc, etc, etc, etc, etc, etc,
etc..................................................

But.

RNA-Based-Life once dominated, DNA-Based-Life came and RNA-Based-life
forms
err *Died*?

Not completely, as currently living organisms do indeed have *some*
RNAs that perform some of the original functions.  But large RNA-based
genomes in free-living non-parasites did disappear.

But their dead?

They're (not 'their') extinct. Just like ichthyosaurs. The only RNA
genomes that remain today belong to small viruses. That is their
remaining useful niche. But that *still* means that RNA is and can be
used as a genome, doesn't it? That they aren't used for large genomes
now does not negate the fact that RNA can be and is used as a genome.

Even a fossil bone has a function as a crude bat.

RNA is not bone. Ed Conrad may think that fossil human penises and
lungs are lying around along with bones. I don't. And RNA does not
fossilize well. Neither for that matter, does DNA.

Just like trilobites.  And ichthyosaurs.  And pterodactyls.

No, No, No.

Arthropod's & reptiles *still* exist.

And trilobites, ichthyosaurs, and pterodactyls did exist in the past,
and *still* don't exist today. They are *extinct*. That other
arthropods and reptiles still do exist doesn't matter. Your claim
requires that trilobites, ichthyosaurs, and pterdactyls still exist.
Going one up on the classification scale doesn't bring them to life
again.

Hmmm. That's a puzzle.

Not really.

Yes, Really.

I explained why the *chemistry* (specifically inherent
stability) of the polymers favor large genomes

No it doesnt. Large genomes cleave far more than small ones.

Well, duh. That is *why* chemistry favors DNA for large genomes. RNA
undergoes scission more often *because* of the more chemically active
hydroxyl at the 2' position.

Especially since RNA-Based-Life *supposedly* evolved so fast,
and has never repeated the feet in 3billion years or so.

Well, "feet" have been invented more than once.

And eyes but not, the fastest critter to ever evolve off the starting
post.

Why is that do you think?

Fastest? Don't you mean "simpler" or "more primitive" *because* a
'living system' that we are discussing uses RNA as a jack-of-all-
trades and master-of-none. The reason why DNA-based organisms have
prevailed and driven RNA-based genomes (except for small viruses) to
near extinction (although it cannot be absolutely ruled out, no modern
free-living organism with an RNA genome has been found to date). The
reason that DNA-based genomes prevail (except in small RNA
viruses...nidoviruses and coronoviruses have the largest RNA genomes
in viruses, about 30-32Kb) is because of the relative stability of
their genomes. That is, DNA is material that evolved to be
*specialized* as genetic material, allowing RNA to perform other
functions it can do better.

Nidoviruses have the largest RNA genome.

http://www.ncbi.nlm.nih.gov/pubmed/16503362

Under what conditions do you think large genome RNA organisms
would be favored.

Errrrrrrrrr.

Still no answer? Under what conditions do you think large genome RNA
organisms would be favored in the present environment?

*Small* RNA genomes in viruses, OTOH, can
compete.

Look. When will you learn that I am never wrong.

Au contraire. You are rarely right.

http://en.wikipedia.org/wiki/Mimivirus

Mimivirus is a large virus *and*, accordingly, has a *DNA* genome.
Not an RNA genome. Poxviruses are also large DNA viruses. What was
your point in pointing this out?

.

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