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.
(...) 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."
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