Origin of Life - Hot Springs

[SelfSim]

Latest hypothesis on life’s origins (abiogenesis), which wraps up current research from multiple parallel streams, here:
The Hot Spring Hypothesis for an Origin of Life

Main hypothesis points, (roughly quoted and summarised from the Abstract), are:

1. origin of life on land in which fluctuating volcanic hot spring pools play a central role;
2. based on experimental evidence that lipid-encapsulated polymers can be synthesized by cycles of hydration and dehydration to form protocells;
3. protocells cycling through wet, dry, and moist phases will subject polymers to combinatorial selection and draw structural and catalytic functions out of initially random sequences, including structural stabilization, pore formation, and primitive metabolic activity;
4. proposes that protocells aggregating into a hydrogel in the intermediate moist phase of wet-dry cycles represent a primitive progenote system. Progenote populations can undergo selection and distribution, construct niches in new environments, and enable a sharing network effect that can collectively evolve them into the first microbial communities;
5. biogenesis begins with simple protocell aggregates, through the transitional form of the progenote, to robust microbial mats that leave the fossil imprints of stromatolites so representative in the rock record;
6. proposes future testing of the hypothesis;
7. compares the oceanic vent with land-based pool scenarios for an origin of life and explores implications for subsequent evolution to multicellular life such as plants;
8. concludes by utilizing the hypothesis to posit where life might also have emerged in habitats such as Mars or Saturn's moon Enceladus;

Note: Study dies not conclude that Earth must have given birth to life in exactly the way they describe .. moreso that life could have arisen on Earth via this path, and could also arise on other worlds in a similar way, assuming Hadean-like starting conditions.

 

[Brightmoon]

there a book called Life on a Young Planet by Andrew Knoll that goes over the first 3 billion years of life on earth and stops at the Cambrian explosion. The book might be a little out dated but it’s a fascinating read . This is the first edition cover

 

[Brightmoon]

This is a brief video explaining how the proto cells might have formed . This is Jack Szostak’s work up until 2009. this is a photo cuz I can’t link sorry . You’ll have to google

 

[Subduction Zone]

View attachment 280328This is a brief video explaining how the proto cells might have formed . This is Jack Szostak’s work up until 2009. this is a photo cuz I can’t link sorry . You’ll have to google

 

[SelfSim]

there a book called Life on a Young Planet by Andrew Knoll that goes over the first 3 billion years of life on earth and stops at the Cambrian explosion. The book might be a little out dated but it’s a fascinating read . This is the first edition cover

Looks like that one's a little more heavily focused on the Evolution part(?) - (I'm not sure).

The really interesting development in the March 2010 OP paper, I think, is the thinking around the pre-biotic chemistry phases (covered points 2, 3 and 4). It is, in turn, based on some pretty heavy reference studies, by other researchers.

The main idea behind it all is that there is no clear cut transition from 'no-life' prechemistries to 'life' bio-chemistries, when it comes to the self-replication phase.

 

[SelfSim]

This is a brief video explaining how the proto cells might have formed . This is Jack Szostak’s work up until 2009. this is a photo cuz I can’t link sorry . You’ll have to google

Yes .. whilst the bulk of the content in that video remains valid, its interesting that it gets its knickers in a knot over what 'information' its talking about. (All too familiar with CFs discussions, I might add).

Ie: in the first part it claims:
‘Early genomes were completely random and contained no information. It was their ability to spontaneously replicate irrespective of sequence that drove growth and division of the fatty acid vesicles’.

then, towards the end, it almost contradicts that statement and says:
‘Just like RNA the nucleotides could both store information and function as enzymes’.

The OP paper, (via its references), clarifies what 'information' means in so far as it introduces the concepts of 'compositional information', ‘compositional assemblies’ and then 'composomes'.

('Compositional information' is intended to be equivalent to the RNA world's sequential information; ‘compositional assemblies’ = biopolymers and; 'composome' = genome).

These concepts will become very important in future research, which is aimed at massive computational processing, in order to demonstrate, via simulations, the validity of the early polymer/lipid self assembly and replication hypothesis, as it relates to abiogenesis.

 

[Subduction Zone]

Yes .. whilst the bulk of the content in that video remains valid, its interesting that it gets its knickers in a knot over what 'information' its talking about. (All too familiar with CFs discussions, I might add).

Ie: in the first part it claims:
‘Early genomes were completely random and contained no information. It was their ability to spontaneously replicate irrespective of sequence that drove growth and division of the fatty acid vesicles’.

then, towards the end, it almost contradicts that statement and says:
‘Just like RNA the nucleotides could both store information and function as enzymes’.

I would not say that is a contradiction. The earliest RNA almost certainly had no information, only the ability to self duplicate. The information and enzyme functions occurred later.

The OP paper, (via its references), clarifies what 'information' means in so far as it introduces the concepts of 'compositional information', ‘compositional assemblies’ and then 'composomes'.

('Compositional information' is intended to be equivalent to the RNA world's sequential information; ‘compositional assemblies’ = biopolymers and; 'composome' = genome).

These concepts will become very important in future research, which is aimed at massive computational processing, in order to demonstrate, via simulations, the validity of the early polymer/lipid self assembly and replication hypothesis, as it relates to abiogenesis.

Yep, many questions are not answered yet. I doubt if we will ever have one single "Aha!!" moment on how life began. Instead like the paper in the OP we will merely make very small advances here and there.

But you do raise a valid point. We do need a better definition of "information" than we have now.

 

[SelfSim]

The earliest RNA almost certainly had no information, only the ability to self duplicate. The information and enzyme functions occurred later.

More like in this idea, the forerunner to RNA is envisaged to contain information about the different types and quantities of molecules within a lipid vesicle assembly and then this is the information which effectively gets replicated and propagated (by process of simple fission).
Full blown RNA evolution then flows on as a consequence of vast, en-masse lipid based networks following that same process.

Its still information which is getting propagated though .. just a different type of it.

 

[Subduction Zone]

More like in this idea, the forerunner to RNA is envisaged to contain information about the different types and quantities of molecules within a lipid vesicle assembly and then this is the information which effectively gets replicated and propagated (by process of simple fission).
Full blown RNA evolution then flows on as a consequence of vast, en-masse lipid based networks following that same process.

Its still information which is getting propagated though .. just a different type of it.

Possibly. From my understanding the only "information" that the first self replicating molecule would have had was how to self replicate. Once that occurs reliably life is all but inevitable.

 

[SelfSim]

Possibly. From my understanding the only "information" that the first self replicating molecule would have had was how to self replicate.

See, I would say that you've distinguished an 'instruction' from 'information' there ..
'Instructions' imply some kind of destination (or end result) .. yet this lipid based vesicle is just demonstrating to us, (hypothetically), behaviours that we then describe as basic chemistry and physics.
Arguably, the most fundamental concept for theoretical physics and chemistry to work, is the concept of 'information' .. so its the concept of 'information' which accounts for the observations/demonstrations which follow. It has to be there for physics and chemistry to have a chance of explaining what follows. (Yet the Shostak content video said there was none).

Once that occurs reliably life is all but inevitable.

Sure.
Life becomes inevitable in that scenario because we define 'life' as being capable of demonstrating Darwinian Evolution .. but definitions can, and do, change .. so its important not let our own definitions skew our thinking about something at the fringe of Evolution's basis of evidence. (Doing so, would also 'inevitably' produce a circular argument).

 

[SelfSim]

Possibly. From my understanding the only "information" that the first self replicating molecule would have had was how to self replicate. Once that occurs reliably life is all but inevitable.

Another way of saying that is Evolution needs populations of information carriers. However, its also equally possible to reach the conclusion that replication is not a prerequisite for selection, but instead, there can be selection for replication - this is, in fact, what these guys are arguing.

 

[SelfSim]

Interesting update which fills in a major abiogenesis 'blank' on how RNA first formed here on Earth:
Scientists announce a breakthrough in determining life's origin on Earth—and maybe Mars, June 23, 2022:

Scientists at the Foundation for Applied Molecular Evolution announced today that ribonucleic acid (RNA), an analog of DNA that was likely the first genetic material for life, spontaneously forms on basalt lava glass. Such glass was abundant on Earth 4.35 billion years ago. Similar basalts of this antiquity survive on Mars today.

1) 100 to 200 nucleotides in length:

Led by Elisa Biondi, the study shows that long RNA molecules, 100-200 nucleotides in length, form when nucleoside triphosphates do nothing more than percolate through basaltic glass.

2) Basaltic Glass readily available (4.3–4.4 billion years ago) on the Hadean Earth surface:

"Basaltic glass was everywhere on Earth at the time," remarked Stephen Mojzsis, an Earth scientist who also participated in the study. "For several hundred million years after the Moon formed, frequent impacts coupled with abundant volcanism on the young planet formed molten basaltic lava, the source of the basalt glass. Impacts also evaporated water to give dry land, providing aquifers where RNA could have formed."

3) Nickel and Borate from the same impact glass:

The same impacts also delivered nickel, which the team showed gives nucleoside triphosphates from nucleosides and activated phosphate, also found in lava glass. Borate (as in borax), also from the basalt, controls the formation of those triphosphates.

4) Atmospheric reduction also accompanied impacts:

The same impactors that formed the glass also transiently reduced the atmosphere with their metal iron-nickel cores. RNA bases, whose sequences store genetic information, are formed in such atmospheres. The team had previously showed that nucleosides are formed by a simple reaction between ribose phosphate and RNA bases.

5) Simplicity of RNA formation .. and Mars surface is the test-bed:

"The beauty of this model is its simplicity. It can be tested by highschoolers in chemistry class," said Jan Špaček, who was not involved in this study but who develops instrument to detect alien genetic polymers on Mars. "Mix the ingredients, wait for a few days and detect the RNA."

So much for beliefs that complex RNA molecules can't form in a (now) lab demonstrated environment, eh?

 

[SelfSim]

Another significant study (dated 2020) reported here:

Spontaneous Emergence of Self-Replicating Molecules Containing Nucleobases and Amino Acids
This one describes how amino acids and nucleobases interwork in the RNA-peptide coevolution hypothesis.

Significantly:

While previously reported nucleic acid-based self-replicating systems rely on presynthesis of (short) oligonucleotide sequences, self-replication in the present systems start from units containing only a single nucleobase. Self-replication is accompanied by self-assembly, spontaneously giving rise to an ordered one-dimensional arrangement of nucleobase nanostructures.

Their conclusion:

We have shown that exponential replicators featuring nucleobases and amino acids can emerge spontaneously from mixtures of relatively simple building blocks.

The findings reinforce the importance of prior autocatalysis research hypotheses and shows how science's incremental approach of combining theory with empirical research can demonstrate the physical feasibility of the occurence of abiogenesis via autocatalysis:

The present system has the advantage over previously reported assemblies of nucleobase analogues in that they form autocatalytically.