New and Interesting Publications Relevant to the Origin of Life

[BillTre]

Exciting times for Origin of Life enthusiasts.
There have been three recent publications that are relevant to origin of life issues.
They are:

A) The moon forming impact may have gotten plate tectonics started early.

A Giant Impact Origin for the First Subduction on Earth​

Open access from Geophysical Research Papers here.
Relevance to the OoL: Some consider recycling of mantle rocks to the surface important because to continues to introduce unweathered rock to the surface (under the oceans) which can be a source for primitive cellular metabolism (eating hydrogen from serpentinization).

B) Plate tectonics may have started earlier than many had thought.
Many thought plate tectonics didn't start until a few hundred thousand years after liquid water formed on the surface. A PNAS AI study of zircons disputes this.
Sediment subduction in Hadean revealed by machine learning.
Open access from PNAS here.

Plate tectonics occurring early also means that there could have been some dry land on early earth. This is another potential environment where early life might have arisen (in terrestrial ponds). Some think this is important because it provides a fresh water site where more phosphorous might have been available.
Otherwise the only dry land might have only been on a few emergent volcanoes, limiting the number of possible freshwater sites.

C) The Last Universal Common Ancestor (LUCA) may have arisen 4.09 to 4.33 billion years ago. Some estimates have put it at 3.4 to 3.8 BYA.

The nature of the last universal common ancestor and its impact on the early Earth system​

This open access Nature Ecology and Evolution paper is found here.
This study claims that LUCA had a hydrogen eating metabolism (acetogen which makes acetate), a 2.5 megabase genome 2,600 protein encoding genes, and an immune system somewhat like Crispr to fight off viruses (intracellular parasites).

This supports the life got started fast school of thought.

All the proteins involved would have required a protein translation system as well as a protein signal recognition system to target the different topological regions of the cell (inside, outside, in the membrane, as well as the inner and outer membrane surfaces).
These are all complex and sophisticated molecular systems.
I have only glanced at this one so far so I may have more to add later.

I highly commend these authors for making these articles open access!

 

[BillTre]

Here is an interesting figure from the LUCA article listed above.

Only the black lineages can be addressed with traditional phylogenetic methods.

The point of this figure is that LUCA was a highly evolved chemical system with >2,000 encoded genes. LUCA is a one of many derivatives of the first autopoietic chemical system at the root of the tree (previous post).
In parallel, other derivatives of the first bounded autopoietic system would have acquired other encoding molecules with different chemical properties.
The collection of these variants at the time of LUCA could have formed an ecology of organisms taking advantage of a few different energy sources.
The encoding molecules could either encode proteins through translational and signal recognition processes, or a simpler direct use of RNAs taking sequence specific conformations with particular chemical skills (ribozymes).

The presence of components of the anti-viral Crispr system implies a robust virus-like population. Genetic parasites are an expected thing by many people.

The first example of such a system (which I would characterize as a bounded autopoietic chemical system) would be a much simpler thing. Basically it just has to make more of itself from environmental resources and divide to make more than two chemicals systems with equivalent properties (important ones).
It also has to raise in some way for simpler beginnings.

 

[pinball1970]

Open access publication by Cardiff University.

https://www.sciencedirect.com/science/article/pii/S0301926824001669?via=ihub

Possible evidence that complex life could have began way earlier than previously thought.

https://phys.org/news/2024-07-compl...llion.html?utm_source=webpush&utm_medium=push

EDIT: @BillTre @jim mcnamara

 

[BillTre]

I checked out this article.
Its mostly about the geochemistry in an area that became isolated from the rest of the ocean when two continents collided together and eventually fused to become one.
This may have created conditions where "higher" lifeforms could have arisen.

Its possible relationship to a primitive animal life form was mentioned but not well demonstrated.

Higher life forms was not well defined from my point of view. I wish they had more information on this.
They talked some about eukaryotes but also about animals that could move (motile).
They referred to other articles that they admitted were disputed about the life forms, but did not really go into that any in their article. The phys.org article had a picture of a blobby thing with irregular peripheral lobes:

There was no reference in the article for the picture or a description.

I could conceivably see this could have evolved into something like a traditional Precambrian Dickensonia organism (hundreds of millions of years later) which has lobes, but much more regularly arranged. Perhaps the first one had a tissue level of organization down, but was not so good at a regular body plan. The Dickensonia has a somewhat bilateral symmetry and an apparent anterior-posterior axis.
Or another way to say it would be the blob dudes may have had a way to pattern cells (either a single cell type or more than one) into functional tissues, but the patterning those tissues into higher organizations may not have yet evolved. (This is all conjectural on my part, but fun.)

Dickensonia

When I think about ancient life forms,, its usually like this:
very first life forms: ??? not seen yet, simpler than prokaryotes (bacteria and archaea).
First known life (from fossils): prokaryotes (bacteria and archaea).
Complex life: prokaryotes (single celled initially)
Intelligent life: thinking metazoans (animals, like us and dogs) and able to communicate (like us)

Early animals, which these guys want to focus on, are probably at a similar level of complexity as plants or fungi (multicellular eukaryotes).
These kinds of differences were not clear to from the article.

They also said the blobs predated known prokaryotes, but did not convincingly show they were eukaryotes. They could have be structured masses of prokaryote cells. Stromatolites are older and considered a kind of colonial prokaryote. They are layered mats of prokaryotes glued together with sediments that accumulate on them. They can get quite large, but are not a similarly patterned.

stromatolite:

 

[javisot20]

I was very impressed by this when I heard about it. Darwin described LUCA as the first, because it was the first, must also be totally simple. We thougt we had confirmed this in 1993, but now in 2024 these results seem to indicate that LUCA is a "narrowing" during the origin of life. It seems that it was not the first nor was it so simple.
(These results will have to be confirmed again)

The new study places LUCA on Earth +/- 4200 million years ago, while the planet is approximately 4600 million years old. Very little time to build reasonable explanations.

What role did LUCA play in that environment an how did that environment arise?
Did that pre-LUCA environment arise by panspermia or abiogenesis?
Was LUCA some kind of organism from that environment? Maybe a virus?

These latest results put us in a much more complex situation, instead of solving our doubts about the origin of life on Earth, we now have more doubts than ever.

Do you have more information on this topic and how it is evolving? Thanks