Researchers from the Georgia Institute of Technology may have made headway in helping determine the origin of life by identifying three different molecules that self-assemble to form a molecular structure with features characteristic of modern RNA.
RNA – or ribonucleic acid – carries out the instructions coded in DNA, but is also thought to have developed before DNA. Many scientists believe nucleic acids – the ‘NA’ of ‘RNA’ – played a key role in the origin of life. A popular theory called the ‘RNA World’ holds that RNA ‘invented’ proteins and eventually DNA, but that begs the question, where did RNA come from? Some believe a chemical or biological process gradually evolved an earlier molecule into RNA, while others chalk it up to some kind of non-enzymatic, geochemical reaction. It’s a chicken-or-egg debate: what biological process could produce a central building block for life itself? If the process wasn’t biological, then what was it and how did it happen?
The new study continues in the tradition of the 1953 Miller–Urey experiment, in which two scientists modeled early-Earth’s conditions with a mixture of gases and an electric current to simulate lightning. That experiment yielded amino acids, supporting the idea that biological molecules can spontaneously emerge from non-biological ones in the right circumstances. Despite that finding, the challenge of devising a scenario in which non-biological reactions create RNA has thus far proven insurmountable.
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