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Tim Tyler · Guest

Paraphrased from my RNA world essay - at: http://originoflife.net/rna_world/

I am seeing a lot of garbage about the RNA world on the net :-|

For example:

``RNA world hypothesis, for example, suggests that short RNA molecules
could have spontaneously formed that would then catalyze their own
continuing replication.''

- http://en.wikipedia.org/wiki/Origin_of_life

``The RNA World hypothesis holds that in the primordial soup (more likely
the primordial sandwich), there were RNA and DNA base pairs floating
around. Since it is of lower energy for base pairs to form a chain, this
would happen with some regularity. However, these chains are not of much
lower energy than free base pairs, so the chains would also break apart
with some regularity. However, some sequences of base pairs have
catalytic properties - catalytic properties which lowers the energy of
that same chain being created. As more and more of these RNA chains are
created, they catalyze the formation of yet more. This causes chains to
form faster than they break down, creating a positive feedback loop.

These chains are proposed to be the first, primitive forms of life.[]''

- http://en.wikipedia.org/wiki/RNA_world_hypothesis

Nonsense like this makes the RNA world hypothesis appear ridiculous.
The problems are stupendous. For one thing, nucleotide isomeric impurity
blocks replication of RNA. For another, there is no plausible way
that primed nucleotides could be supplied.

AFAIK, nobody seriously interested in the origin of life believes this
dumb hypothesis.

Proponents of the RNA world should take more care to emphasise that the
notion that the RNA world was primitive is *not* biologically plausible -
rather than associating themselves with the idea.

The RNA world was *obviously* constructed by more primitive agents -
(of which there are no shortage of candidates) - rather than forming
out of nothing.

The RNA world is a fine piece of science. I just wish people would stop
muddling it together with a load of complete garbage about the RNA world
being first.
--
__________
|im |yler http://timtyler.org/ tim@tt1lock.org Remove lock to reply.

adam retchless · Guest

Hi Tim,

You>re free to edit those Wikipedia articles if you feel like it, or at
least you could make a comment on the discussion page for those articles.

The quality of Wikipedia articles varies greatly since anyone can write
and edit an article. My hope is that Wikipedia is approaching its
adolescence, where it attracts a fair number of authors with significant
expertise on the topics they are writing. I hope that lesser experts
will recognize when they have encountered the work of greater expert and
not ruin it.

have a good one,
adam

Tim Tyler wrote:
[quote]Paraphrased from my RNA world essay - at: http://originoflife.net/rna_world/

I am seeing a lot of garbage about the RNA world on the net :-|

For example:

``RNA world hypothesis, for example, suggests that short RNA molecules
could have spontaneously formed that would then catalyze their own
continuing replication.''

- http://en.wikipedia.org/wiki/Origin_of_life

``The RNA World hypothesis holds that in the primordial soup (more likely
the primordial sandwich), there were RNA and DNA base pairs floating
around. Since it is of lower energy for base pairs to form a chain, this
would happen with some regularity. However, these chains are not of much
lower energy than free base pairs, so the chains would also break apart
with some regularity. However, some sequences of base pairs have
catalytic properties - catalytic properties which lowers the energy of
that same chain being created. As more and more of these RNA chains are
created, they catalyze the formation of yet more. This causes chains to
form faster than they break down, creating a positive feedback loop.

These chains are proposed to be the first, primitive forms of life.[]''

- http://en.wikipedia.org/wiki/RNA_world_hypothesis

Nonsense like this makes the RNA world hypothesis appear ridiculous.
The problems are stupendous. For one thing, nucleotide isomeric impurity
blocks replication of RNA. For another, there is no plausible way
that primed nucleotides could be supplied.

AFAIK, nobody seriously interested in the origin of life believes this
dumb hypothesis.

Proponents of the RNA world should take more care to emphasise that the
notion that the RNA world was primitive is *not* biologically plausible -
rather than associating themselves with the idea.

The RNA world was *obviously* constructed by more primitive agents -
(of which there are no shortage of candidates) - rather than forming
out of nothing.

The RNA world is a fine piece of science. I just wish people would stop
muddling it together with a load of complete garbage about the RNA world
being first.
[/quote]
--
Adam Retchless
to send me email, replace “SEVEN” with “7” in my reply-to address.

Jim Menegay · Guest

adam retchless <acrSEVEN+@pitt.edu> wrote in message news:<bt4qpf$1u31$1@darwin.ediacara.org>...
[quote]Hi Tim,

You>re free to edit those Wikipedia articles if you feel like it, or at
least you could make a comment on the discussion page for those articles.

The quality of Wikipedia articles varies greatly since anyone can write
and edit an article. My hope is that Wikipedia is approaching its
adolescence, where it attracts a fair number of authors with significant
expertise on the topics they are writing. I hope that lesser experts
will recognize when they have encountered the work of greater expert and
not ruin it.

have a good one,
adam

Tim Tyler wrote:
Paraphrased from my RNA world essay - at: http://originoflife.net/rna_world/

I am seeing a lot of garbage about the RNA world on the net :-|

For example:

``RNA world hypothesis, for example, suggests that short RNA molecules
could have spontaneously formed that would then catalyze their own
continuing replication.''

- http://en.wikipedia.org/wiki/Origin_of_life

``The RNA World hypothesis holds that in the primordial soup (more likely
the primordial sandwich), there were RNA and DNA base pairs floating
around. Since it is of lower energy for base pairs to form a chain, this
would happen with some regularity. However, these chains are not of much
lower energy than free base pairs, so the chains would also break apart
with some regularity. However, some sequences of base pairs have
catalytic properties - catalytic properties which lowers the energy of
that same chain being created. As more and more of these RNA chains are
created, they catalyze the formation of yet more. This causes chains to
form faster than they break down, creating a positive feedback loop.

These chains are proposed to be the first, primitive forms of life.[]''

- http://en.wikipedia.org/wiki/RNA_world_hypothesis

Nonsense like this makes the RNA world hypothesis appear ridiculous.
The problems are stupendous. For one thing, nucleotide isomeric impurity
blocks replication of RNA. For another, there is no plausible way
that primed nucleotides could be supplied.

AFAIK, nobody seriously interested in the origin of life believes this
dumb hypothesis.

Proponents of the RNA world should take more care to emphasise that the
notion that the RNA world was primitive is *not* biologically plausible -
rather than associating themselves with the idea.

The RNA world was *obviously* constructed by more primitive agents -
(of which there are no shortage of candidates) - rather than forming
out of nothing.

The RNA world is a fine piece of science. I just wish people would stop
muddling it together with a load of complete garbage about the RNA world
being first.
[/quote]
Tim,

Should you decide to edit the article, please be cautious in your claims.
The idea that an RNA world existed should indeed be separated from the
idea that the RNA world was first. But, while I agree with you that
it probably WASN>T first, I would probably disagree that this is "obvious".
My reading of the literature suggests that there is still widespread
hope, even among the "insiders", that it might have been THE origin.

As evidence that it MIGHT have been first, note that ribose is a natural
polymerization product of formaldehyde and that adenine is a natural
polymerization product of cyanide. The other bases can arise from adding
a bit of CO to the mix. It is a little "spooky", to my mind, that
a genetic capture medium should seem so plausibly pre-biotic. Der Herr
Gott may be being malicious in this case.

There are serious problems, as we both know, with the notion that RNA
was first (chirality being the most formidable in my mind). But,
those problems don>t make the theory a "load of complete garbage".

Jim

Tim Tyler · Guest

Jim Menegay <jamenegay@ra.rockwell.com> wrote or quoted:

[quote]The idea that an RNA world existed should indeed be separated from the
idea that the RNA world was first. But, while I agree with you that
it probably WASN>T first, I would probably disagree that this is "obvious".
My reading of the literature suggests that there is still widespread
hope, even among the "insiders", that it might have been THE origin.
[/quote]
No doubt some hope - but I reckon that now not many are left:

``But where did RNA come from? To date, no one has been able to form RNA
under in the laboratory under conditions that mimic those believed to
have existed on primitive Earth. Some scientists also question whether
nucleic acids with a backbone of ribose, or any other sugar molecule,
would be stable enough to survive the harsh conditions of early Earth.

So it is generally agreed that RNA must have evolved from an earlier
form. While TNA is a good candidate, other polymers that exhibit
self-replication and base pairing could have evolved into RNA. Pyranosyl
RNA (p-RNA) and peptide nucleic acid (PNA) are two of these
alternatives.''

- http://nai.arc.nasa.gov/news_stories/news_detail.cfm?ID=189

"it is generally agreed that RNA must have evolved from an earlier form".

I>m pleased that scientists have "finally" come around to this idea.

Now at least (almost) everyone agrees that there were previous genetic
materials that were *so* old and primitive that they have been completely
relplaced by the ones that came after them.

No longer will I have to bother addressing the question of what happened
to traces of the earlier genetic material - since now "almost everyone"
agrees that pre-RNA genes *were* there - and that they were
/completely/ superseded by more advanced technology.

I>m sure my comments would be widely regarded as overstated.

Feel free to insert more "IMHO"s - until they are sufficiently toned down
for your tastes ;-)
--
__________
|im |yler http://timtyler.org/ tim@tt1lock.org Remove lock to reply.

adam retchless · Guest

Jim Menegay wrote:

[quote]
There are serious problems, as we both know, with the notion that RNA
was first (chirality being the most formidable in my mind). But,
those problems don>t make the theory a "load of complete garbage".

Jim

[/quote]
From what I>ve read (The Molecular Origins of Life : Assembling Pieces
of the Puzzle edited by Andri Brack, 1998), the atmosphere of the early
earth was "weakly reducing", whereas the production of ribonucleotides
would have required a "strongly reducing" atmosphere. Therefore, RNA is
the result of life, not the cause.

I suppose that this doesn>t rule out local strongly reducing
environments. Unfortunately, I no longer have possession of the book.

--
Adam Retchless
to send me email, replace “SEVEN” with “7” in my reply-to address.

TomHendricks474 · Guest

Some scientists also question whether
nucleic acids with a backbone of ribose, or any other sugar molecule,
would be stable enough to survive the harsh conditions of early Earth. >>

TH
No I think you have it backwards. It wasn>t independent life that had to
'survive the harsh conditions of early earth'. It was the other way around
That which was best adapted to the harsh conditions of early earth - was life.

It is a 180 degree shift - but you have to see it or
nothing makes sense about the OOL.

TomHendricks474 · Guest

<< From what I>ve read (The Molecular Origins of Life : Assembling Pieces
of the Puzzle edited by Andri Brack, 1998), the atmosphere of the early
earth was "weakly reducing", whereas the production of ribonucleotides
would have required a "strongly reducing" atmosphere. Therefore, RNA is
the result of life, not the cause.

I suppose that this doesn>t rule out local strongly reducing
environments. Unfortunately, I no longer have possession of the book.
[quote]
[/quote]

Things may be changing back to the atmosphere in Miller>s flasks.

Astronomy Mag, July 03, had the article "Mysteries of atmospheres revealed". N.
Lubick (astronomy.com)
Quote,"...the lack of a siderite rich geologic record indicates that CO2
couldn>t have been the primary temperature raising gas."

Also note that recent post on this newsgroup suggesting that the Issua rocks
from Greenland seem to be life at 3.7 bya - thus pushing back the origin to
near or in the Hadean period of bombardment, high heat, oppressive atmosphere,
greenhouse gases, uv, tides that pulled the CRUST 60 meters twice a day.
TH

Jim Menegay · Guest

adam retchless <acrSEVEN+@pitt.edu> wrote in message news:<btaau5$2kd9$1@darwin.ediacara.org>...
[quote]Jim Menegay wrote:

There are serious problems, as we both know, with the notion that RNA
was first (chirality being the most formidable in my mind). But,
those problems don>t make the theory a "load of complete garbage".

Jim

From what I>ve read (The Molecular Origins of Life : Assembling Pieces
of the Puzzle edited by Andri Brack, 1998), the atmosphere of the early
earth was "weakly reducing", whereas the production of ribonucleotides
would have required a "strongly reducing" atmosphere. Therefore, RNA is
the result of life, not the cause.

I suppose that this doesn>t rule out local strongly reducing
environments. Unfortunately, I no longer have possession of the book.
[/quote]
RNA is actually the LEAST reduced of all conceivable organic
macromolecules. So, the weakness of the reducing atmosphere
actually argues FOR RNA. Of course, Tim will point out that it also
argues for an inorganic origin of life.

But even Tim>s clay golems will have to find a locally reducing
environment in order to form their organic replacements.

Personally, I expect to have no trouble finding a local reducing
environment for my organic origin theories. I don>t see weakness
of the global reducing environment as placing any constraints on
the origin, because I believe that a heterotrophic origin (using
widespread abiogenic organics) is not likely.


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