RNA world creation breakthrough

[ursaminortaur]

Scientists have uncovered a simple chemical path from small organic molecules abundant on the early Earth to RNA molecules via percolation through basaltic glass which was also common on Earth.


https://phys.org/news/2022-06-scientists-breakthrough-life-earthand-mars.html

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.
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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.

"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."

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.

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.

"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."

The same rocks resolve the other paradoxes in making RNA in a path that moves all of the way from simple organic molecules to the first RNA. "For example, borate manages the formation of ribose, the 'R' in RNA," Benner added. This path starts from simple carbohydrates that could "not not" have formed in the atmosphere above primitive Earth. These were stabilized by volcanic sulfur dioxide, and then rained to the surface to create reservoirs of organic minerals.

Thus, this work completes a path that creates RNA from small organic molecules that were almost certainly present on the early Earth. A single geological model moves from one and two carbon molecules to give RNA molecules long enough to support Darwinian evolution.