Theoretical origin of life: basalt glass fantasy (Introduction)

by David Turell , Saturday, September 04, 2021, 17:38 (1176 days ago) @ David Turell

Another lab study:

https://www.nature.com/articles/s41557-021-00772-5

"Abstract
Catalytic nucleic acids, such as ribozymes, are central to a variety of origin-of-life scenarios. Typically, they require elevated magnesium concentrations for folding and activity, but their function can be inhibited by high concentrations of monovalent salts. Here we show that geologically plausible high-sodium, low-magnesium solutions derived from leaching basalt (rock and remelted glass) inhibit ribozyme catalysis, but that this activity can be rescued by selective magnesium up-concentration by heat flow across rock fissures. In contrast to up-concentration by dehydration or freezing, this system is so far from equilibrium that it can actively alter the Mg:Na salt ratio to an extent that enables key ribozyme activities, such as self-replication and RNA extension, in otherwise challenging solution conditions. The principle demonstrated here is applicable to a broad range of salt concentrations and compositions, and, as such, highly relevant to various origin-of-life scenarios."

Clear commentary:

https://www.sciencealert.com/scientists-identify-a-mixture-of-salts-that-could-have-spa...

"New research looking at how the conditions on primordial Earth might have produced life has identified a mixture of salts that, mixed with heat flows from molten rock, could potentially have contributed to the formation of self-replicating biomolecules.

***

"In this case, scientists looked at the mixture of magnesium (Mg) and sodium (Na) as it might have been on Earth in its earliest years: for RNA folding to work, a relatively high concentration of doubly charged magnesium ions and a lower concentration of singly charged sodium is required.

"'Accordingly, the question arises as to which environments on early Earth might have provided suitable salt conditions for such prebiotic processes. One geologically probable process that produces saline environments is the leaching of salts from basalt," the international team of researchers writes in their study.

"'As a primary partial melt of the Earth's mantle, basalt is one of the most abundant rock types to be expected in the Earth's early crust, as well as the crust of other terrestrial planets in our Solar System."

"The team synthesized basaltic glass – which naturally occurs on Earth when melted basalt is rapidly cooled (by contact with ocean water, for instance) – and characterized it in its various forms, including both rock and glass.

***

"Together, convection and thermophoresis increase the number of magnesium ions in the mix, creating conditions where self-replicating RNA can occur, the study shows. The same sort of chemical reactions may have played out on Earth 4 billion years ago.

"This leaching of salts from basalt – found in abundance in Earth's mantle – fits the template for the RNA world hypothesis to work, the research shows. What's more, it widens out the possibilities in terms of salt mixes that may have helped spark life.

"'The principle demonstrated here is applicable to a broad range of salt concentrations and compositions, and, as such, highly relevant to various origin-of-life scenarios," write the researchers in their published paper."

Comment: All this shows is if RNA is already around the salts help it fold. The author of the commentary shows the usual thoughtless hopefulness about these studies. So what made the RNA from those amino acids which just happen to be lying around in just the right structural organization to become RNAs? RNAs must come first!!!