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Necessary cookies are absolutely essential for the website to function properly. Alternatively, they could convert thiouridine into deoxyribose, which is very closely related to deoxyadenosine and may also have been a precursor of early DNA building blocks. The team showed that in a few chemical-reaction steps, which plausibly could have occurred in a pre-biotic world, they could convert this precursor of an RNA building block into a DNA building block - deoxyadenosine, which forms the letter “A” in the modern, four-letter DNA code. The latter was likely present on Earth before life arose, and could have been a chemical precursor of the nucleoside building blocks of early RNAs. In the new study, the scientists combined insights from that investigation with recent findings from Sutherland and his lab on a compound called thiouridine. In a study published in 2017 for example, Krishnamurthy and colleagues at Scripps Research identified a compound that plausibly was present on the pre-biotic Earth and could have performed the crucial task of linking RNA building blocks into larger, chain-like RNA strands - and could have done the same for the building blocks of DNA and proteins. RNA and DNA may have arisen all at once in first life formsĪlthough origin-of-life researchers in recent decades have largely come to embrace the RNA World hypothesis, Sutherland, Krishnamurthy, Harvard’s Jack Szostak and others have accumulated evidence that RNA and DNA may have arisen more or less all at once in the first life forms.