Two new papers have proposed a new theory that proteins were involved in the origin of life on Earth, alongside RNA.

The claim challenges the dominant “RNA-world” hypothesis which says only nucleic acids were the primary molecules responsible for starting the process. The papers were published in Molecular Biology and Evolution, as well as Biosystems.  

The scientists, from the University of North Carolina at Chapel Hill and the Univeristy of Auckland, New Zeland, present a “peptide-RNA” hypothesis which says small proteins and nucleic acids worked closely together for the first living cells on Earth to be born over four billion years ago, creating the first signs of biology. 

Co-author, Charles Carter, explained, “Until now, it has been thought to tbe impossible to conduct experiments to penetrate the origins of genetics. But we have now shown that experimental results mesh beautifully with the ‘peptide-RNA’ theory, and so these experiments provide quite compelling answers to what happened at the beginning of life on Earth.”

The idea is that the two enzyme super families, with 10 amino acids each, disrupt the original theory. These 20 amino acids are ancient and their remnants are present in all living cells, underscoring their importance. Called aminoacyl-tRNA synthetases (aaRSs), they link amino acids to RNA strings, playing an important role in the essential life process of converting genes intro proteins. 

Peter Wills, the other author of the studies, added, “The enforcement of the relationship between genes and amino acids depends on aaRSs, which are themselves encoded by genes and made of amino acids. The aaRSs, in turn, depend on that same relationship. There is a basic reflexivity at work here. Theorist Douglas  Hofstadter called it a ‘strange loop.’ We propose that this, played a crucial role in the self-organisation of biology when life began on Earth. Hofstadter argued that reflexivity furnishes the force of driving the growth of complexity.”

He continued to express hope that their research will prompt others to consider their theory as a viable one to explain the origin of life, despite the already existing hypothesis. 

Cater concluded, “Compared to the RNA-world hypothesis, what we’ve outlined is simply a much more probable scenario for the origin of life. We hope our data and the theory we’ve outlined in these papers will stimulate discussion and further research on questions relevant to the origins of life. 

“That theory is so alluring and expedient that most people just don’t think there’s an alternative. But we are very confident there is.”

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