A team of researchers from the Foundation for Applied Molecular Evolution says that ribonucleic acid (RNA), which is similar to DNA and was probably the first genetic material for life, forms naturally on basalt lava glass.
Glass like this was abundant on Earth 4.35 billion years ago.
Mars today has similar ancient basalts.
Steven Benner, co-author of the new study published in the journal Astrobiology thinks:
“Communities studying the origins of life have diverged in recent years.
“One community re-visits classical questions with complex chemical schemes that require difficult chemistry performed by skilled chemists.”
Due to the complexity of this chemistry, it can’t explain how life on Earth began, according to the co-author.
In comparison, they adopted a more straightforward method.
The work, led by Elisa Biondi, demonstrates that long RNA molecules of 100-200 nucleotides develop when nucleoside triphosphates simply percolate through basaltic glass.
“Basaltic glass was everywhere on Earth at the time,” said Earth scientist Stephen Mojzsis.
“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 effects delivered nickel, which the researchers discovered produces nucleoside triphosphates from nucleosides and activated phosphate, both of which are contained in lava glass. Borate (as in borax) regulates the synthesis of those triphosphates, which are also found in basalt.
With their metal iron-nickel cores, the identical impactors that produced the glass also decreased the atmosphere transiently. In these conditions, RNA bases, which contain genetic information, are formed. Nucleosides are generated by a simple interaction between ribose phosphate and RNA bases, according to the researchers.
“The beauty of this model is its simplicity. It can be tested by highschoolers in chemistry class,” Jan Paek, who was not engaged in this research but is working on a system to identify extraterrestrial genetic polymers on Mars, said.
“Mix the ingredients, wait for a few days and detect the RNA.”
The same rocks that explain how the first RNA was made also explain how the other problems with making RNA were solved.
“For example, borate manages the formation of ribose, the ‘R’ in RNA,” Benner explained.
This process begins with basic carbohydrates that “could not” have evolved in the atmosphere above prehistoric Earth. These were stabilized by volcanic sulfur dioxide, which was later rained to the surface, forming organic mineral reservoirs.
As a result, this research completes a pathway that leads to the production of RNA from tiny organic compounds that were very certainly present on the early Earth. A single geological model progresses from one to two carbon atoms to RNA molecules long enough to permit Darwinian evolution.
“Important questions remain,” Benner cautions. “We still do not know how all of the RNA building blocks came to have the same general shape, a relationship known as homochirality.”
In the same way, the links between the nucleotides in the material made on basaltic glass can be different. The significance of this is unknown.
The planet Mars is crucial to this revelation since the same minerals, glasses, and impacts were found on Mars of that antiquity.
Continental drift and plate tectonics, which buried most Earth rocks older than 4 billion years, have not occurred on Mars.
As a result, rocks from the relevant period remain on Mars’ surface.
Recent Mars missions have discovered all of the necessary rocks, including borate.
“If life emerged on Earth via this simple path, then it also likely emerged on Mars,” Benner added.
“This makes it even more important to seek life on Mars as soon as we can.”
Image Credit: Getty
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