(ORDO NEWS) — RNA can spontaneously form when component molecules are filtered through basalt glass, according to new research, and this could explain the origin of life on Earth. It will also tell you where to look for it in other worlds.
The researchers acknowledge that the discovery leaves some questions unanswered, but argue that it provides a clear and surprisingly simple answer to one of the biggest questions in science.
The theory of evolution and genetics combine and demonstrate how the simplest forms of life could have evolved. However, they left unresolved the question of how these first life forms could have come about.
Nucleotides, which form the basis of DNA and RNA, have been found in meteorites, but explaining how they come together has proved much more difficult. An article in the journal Astrobiology claims to answer this question by showing that basalt glass causes nucleoside triphosphates to join together in RNA strands.
One thing that the Earth did not lack at the time of the emergence of life was basalt glass.
“For several hundred million years after the formation of the Moon, frequent impacts, combined with abundant volcanism on the young planet, formed molten basaltic lava, the source of basalt glass,” said study co-author Professor Stephen Moizsis of the University of Colorado.
“The impacts also evaporated water to give dry land, providing aquifers where RNA could form.”
No extreme conditions required – the authors have demonstrated impressive rates of synthesis of RNA molecules 90-150 nucleotides long at 25º C (77º F) and pH 7.5, with some reaching 300 nucleotides in length.
“A small impact area on Hadei’s surface, containing only a few metric tons of shattered and water-soaked glass, could produce about a gram of RNA per day,” the authors write.
Hence, they conclude, “polyribonucleotides would be available if there were triphosphates.”
Meanwhile, evidence for nucleotide bases in some meteorites continues to grow, suggesting they could have been delivered to the early Earth from space.
These bases are converted to nucleosides in reduced atmospheres, such as on the early Earth after asteroid impacts. Previously, team members had demonstrated that nickel, which is abundant in some meteorites, catalyzes nucleosides and phosphate to form triphosphates.
This leaves the question of whether these RNA molecules are enough to ignite life. The question remains how long RNA must exist before it can support Darwinian evolution, with estimates ranging from 50 to 5000 nucleotides.
“The beauty of this model lies in its simplicity. This can be tested by high school students in chemistry class,” said Jan Spaczek, PhD in biomolecular science, who was not involved in the study.
If the findings of the researchers are correct, then we should thank basalt for the fact that we exist. Other materials present on the early Earth, such as quartz, did not cause nucleotides to bind in the same way.
By the way, Mars was equally rich in basalt glass. Unlike Earth, most of this material remains close to the surface, and is available for exploration by future missions.
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