Re: OoL – out at first base?

On Tue, 10 Dec 2024 11:20:56 +1100, MarkE <me22over7@gmail.com> wrote:

On 10/12/2024 8:57 am, erik simpson wrote:

On 12/9/24 2:05 AM, MarkE wrote:

On 9/12/2024 5:20 pm, erik simpson wrote:

On 12/8/24 9:54 PM, MarkE wrote:

We need prebiotic formation and supply of nucleotides for RNA world,
and other models at some stage. The scope of the problem of the
supply of these precursors is prone to underestimation.
>
Nucleotides are chemically challenging in terms of the prebiotic
synthesis and assembly of their three constituents of nitrogenous
base, sugar and phosphate group.
>
Harder again are the requirements for supply of these building
blocks. You need (eventually) all canonical bases in sufficient
concentration, purity, chirality, activation, distribution,
location, etc.
>
But the greatest problem I think is this: time. How long must you
maintain the supply described above in order to assemble a
self-replicating RNA strand? And even if you managed that, how much
more time is needed before reaching a protocell capable of
self-synthesising nucleotides? One million years? One hundred
million years?
>
A hypothised little warm pond with wetting/drying cycles (say) must
provide a far-from-equilibrium system...for a million years...or
hundreds of millions of years. You can’t pause the process, because
any developing polymers will fall apart and reset the clock.
>
What are the chances of that kind of geological and environmental
stability and continuity?
>
Therefore, the formation of an autonomous protocell naturalistically
has vanishingly small probability.
>

The LUCA (last universal common ancestor) lived about 200 My after
the formation of the moon.  There's a very outside chance it lived of
Mars. That would make the proximity of the moon's formation a little
easier, but surviving the launch from Mars and months-long trip to
earth isn't very likely.
>
The first life probably in something like a "deep smoker" with lots
clay available.  Clay is a fine surface to catalize organic compounds.
>

>
This makes the problem of time worse. If the first protocell capable
of self-synthesising nucleotides developed this way, you need a "deep
smoker" (or localised group) operating steadily for millions of years.
>
Also, you no longer have wetting and drying cycles, which seem
indispensable to support concentration of reactants, polymerisation, etc.
>

No you don't. The generation time for microbes in on the order of hours.
  Self-catalyzing time for a strand of RNA is probably on the order of
minutes.  A black smoker need only be present for few years, and the
early earth had a much hotter interior means that there were at least
millions of them.  As SJ Gould remarked "life may be as common as
quartz". Indeed.  All you need is hot water and a thermal or chemical
gradient and you're good to go.
 

>
"All you need is hot water and a thermal or chemical gradient and you're
good to go."
>
We have a very different understanding of what is involved in the
formation of life. I'm with these leading OoL researchers (Damer and
Deamer):
>
“[OoL research has] been mainly focused on individual solution chemistry
experiments where they want to show polymerization over here, or they
want to show metabolism over here, and Dave and I believe that it's time
for the field to go from incremental progress to substantial progress.
So, these are the four points we've come up with to make substantial
progress in the origin of life, and the first one is to employ something
called system chemistry, having sufficient complexity so instead of one
experiment say about proteins, now you have an experiment about the
encapsulation of proteins for example, and informational molecules built
from nucleotides in an environment that would say be like an analog of
the early Earth, build a complex experiment. Something we're calling
sufficient complexity, and all of these experiments have to move the
reactions away from equilibrium. And what do we mean by that? Well, in
in your high school chemistry experiments, something starts foaming
something changes color and then the experiment winds down and stops.
Well, life didn't get started that way. Life got started by a continuous
run-up of complexity and building upon in a sense nature as a ratchet.
So we have to figure out how to build experiments that move will move
away from equilibrium...”
>
“You can't sit in a laboratory just using glassware. You have to go to
the field. You have to go to hot springs, you have to go to […] Iceland
and come check and sit down and see what the natural environment is
like, rather than being in the ethereal world of pure reactants and
things like that...”
>
Source: A new model for the origin of life: A new model for the origin
of life: Coupled phases and combinatorial selection in fluctuating
hydrothermal pools. https://youtu.be/nk_R55O24t4?feature=shared

I agree with Deamer and Damer quoted above.  Do they agree with your
statement below?

"Therefore, the formation of an autonomous protocell naturalistically
has vanishingly small probability."

--
To know less than we don't know is the nature of most knowledge