Re: DNA, RNA and Protein questions

On Mar 18, 3:10 pm, Bill <spintro...@xxxxxxxxxxx> wrote:
On Mar 18, 2:41 pm, hersheyh <hershe...@xxxxxxxxx> wrote:

On Mar 17, 9:26 pm, Bill <spintro...@xxxxxxxxxxx> wrote:
Tell them what? That viruses don't work without a DNA based host?

Your right however I should have clarified. A self sustaining genome.

Clarify. Bull ***. You were unaware of RNA genomes.

If that makes you sleep tonight.

And by "self sustaining" I mean carrying *all* the tools to
independently replicate.

That may be necessary now, but why do you assume that it was required as
life began?

Well, using your (not you personally) own logic.

*If* the remnants of RNA-World, are left over.

Remnants.  Evidence.  Not actual organisms.

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. Just like
trilobites. And ichthyosaurs. And pterodactyls.

Hmmm. That's a puzzle.

Not really. I explained why the *chemistry* (specifically inherent
stability) of the polymers favor large genomes that use DNA genomes in
pretty much any environment in which they could exist. You, OTOH,
have not provided any justification for your assertion that conditions
now are *more* favorable for large RNA-based genomes.

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. Under what conditions
do you think large genome RNA organisms would be favored. *Small* RNA
genomes in viruses, OTOH, can compete.

Remnants like "RNA", "Ribosomes", "virus genomes". etc etc etc.

Where are the "RNA 'self replicating-self sustaining' life forms"?

Replaced by organisms with DNA genomes.  

Actually, nearly all the part's they do require are not based on DNA
at all.

Such as?

Curious. Really curious.

As I mentioned, DNA is significantly more chemically stable than RNA.

Funny, when I said they had differen't properties you seemed to throw
a hissy fit.

Your claim was that NTPs and dNTPs were chemically radically
different. They aren't. The stability is just about the only
different property of DNA as opposed to RNA. It has significance, but
that still doesn't mean that RNA and DNA are chemically radically
different. Both are composed of nucleotides linked by adding a 5'
triphosphate end to a 3'OH of the growing chain and use template-copy
for synthesis. Both can contain sequence information, with RNA
containing it less stably.

An RNA-only independent organism of any substantial genomic size
(much larger that of dsRNA viruses) would have to have a highly redundant
genome (many copies of an individual gene) rather than just a few copies of each
'gene'.  This necessary inefficiency would be feasible in the absence
of more efficient organisms like modern DNA-based genomes.  But it was
likely not a feasible lifestyle after such organisms evolved.

That is like saying arms and legs dropped off when birds evolved
wings.
Sorry, it's just stupid.

No. It is saying that organisms with DNA-based genomes have a more
stable genome and that type of genome is favored over RNA-based
genomes *specifically* when the genome is large. Small genomes *can*
be RNA. Besides, bird wings *are* arms (forelimbs). Arms and legs
never dropped off. They changed.

If they died off, why haven't they evolved again, and again, and
again.

See above.

Why? There was nothing that explained the paradox.

The only niche in which RNA genomes can continue to exist today are
viral or viral-like. Because the larger genome niches are filled by
the inherently more efficient DNA-based genomes.

Inventing DNA as a *specialized* and chemically more stable
form of 'genome' is a substantial advance over RNA performing that
function.  The 'invention' of DNA genomes allowed larger and more
complicated genomes to exist in a reproductively efficient form with
less genomic redundancy needed.

And that benefits the viruses how? Exactly?

Viruses are the only genomes currently small enough to allow RNA-based
genomes as a competitive equal to DNA.

That does not mean that DNA is perfect.  Even now the maximum
number of protein-coding genes appears to be in the range of a few
10,000 different genes.  Even in humans.

Oh dear.

Everythings here. Everything they need. It would be much easier to get
a foothold now, than in a RNA-World. So where are they?

That is a stupid idea, among a long string of stupid ideas.  When
organisms go extinct, they do not reappear in exactly the same way.

You are stupid.
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You cannot say

"RNA-Based-Life rose very quickly. But has never arisen since".

I cannot exclude the possiblity that some RNA viruses have arisen
since. Small genomes is the environmental niche in which RNA genomes
survive today.

In one thread

And then say

"Eyes have evolved at least 40 different times"
In another

None of these eyes are precisely identical to the others.

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