While some say life emerged from simple chains of molecules, others say early chemical reactions formed self-replicating RNA.
[7 Theories on the Origin of Life]A new study provides evidence for the RNA idea, which is known as the “RNA world hypothesis.”
Modern RNA, alongside its sugar and phosphate backbone, is made of four main building blocks: nucleobases called adenine (A), cytosine (C), guanine (G), and uracil (U).
But it turns out that early RNA may have had one nucleobase that isn’t part of the modern form.
His only quibble is the claim that inosine is more plausible in the making of primitive RNA than other alternative bases, Deamer said.
He doesn’t yet think the other bases should be excluded, since “this is a fairly broad claim … based on a highly specific chemical reaction,” Deamer told Live ScienceBut because inosine can be easily derived from another base pair, adenine, it makes the process of originating life “easier” than if you had to make guanine from scratch, said John Sutherland, a researcher into the chemical origins of molecular biology at the MRC Laboratory of Molecular Biology in the U.K., who was not part of the study either.
Inosine had earned this reputation because it works a very specific job in a form of RNA called transfer RNA, which decodes genetic information.
That would have made it a poor molecule for giving unique instructions to form new RNA, because there wouldn’t have been clear direction for what inosine could bind with.
But this study showed that inosine, in the early world context where RNA first emerged, doesn’t wobble, but instead pairs reliably with cytosine, he added.
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