(ORDO NEWS) — Scientists at the Foundation for Applied Molecular Evolution announced today that ribonucleic acid (RNA), an analogue of DNA that was likely the first genetic material for life, is spontaneously formed on basalt lava glass. Such glass was abundant on Earth 4.35 billion years ago. Similar basalts of such antiquity have been preserved on Mars today.
A study led by Elisa Biondi shows that long RNA molecules, 100-200 nucleotides long, are formed when nucleoside triphosphates do nothing more than seep through basalt glass.
“Basalt glass was everywhere on Earth at that time,” said Steven Moizhys, an earth scientist who was also involved in the study.
“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. As a result of impacts, water evaporated, forming dry land, which provided aquifers in which RNA could form.
These same impacts delivered nickel, which the team showed produces nucleoside triphosphates from nucleosides and activated phosphate, also found in lava glass. Borate (as in bura), also from basalt, controls the formation of these triphosphates.
The same impactors that formed the glass also briefly reduced the atmosphere with their metallic iron-nickel cores. RNA bases, the sequences of which store genetic information, are formed in such atmospheres. The team had previously shown that nucleosides are formed from a simple reaction between ribose phosphate and RNA bases.
“The beauty of this model lies in its simplicity. It can be tested by schoolchildren in a chemistry class,” said Jan Spaczek, who was not involved in this study but is developing an instrument to detect alien genetic polymers on Mars. “Mix the ingredients, wait a few days and find the RNA.”
The same rocks resolve other paradoxes in the creation of RNA, going all the way from simple organic molecules to the first RNA.
Thus, this work completes the path that creates RNA from small organic molecules that were almost certainly present on the early Earth. The unified geologic model moves from one and two carbon molecules to RNA molecules long enough to support Darwinian evolution.
“Important questions remain,” Benner cautions. “We still don’t know how all the building blocks of RNA came to have the same shape, which is called homochirality.” Similarly, bonds between nucleotides can be different in a material synthesized on basalt glass. The meaning of this is unknown.
Mars is relevant to this article because the same minerals, glasses, and influences were also present on Mars of that antiquity.
However, Mars was not affected by the continental drift and plate tectonics that buried most of the rocks from Earth older than 4 billion years. Thus, rocks of the corresponding time remain on the surface of Mars. Recent missions to Mars have found all the necessary rocks, including borate.
“If life originated on Earth in such a simple way, then most likely it originated on Mars,” Benner said. “This makes it even more important to search for life on Mars as soon as possible.”
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