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Importantly they also discovered all five nitrogenous bases — adenine, guanine, cytosine, thymine, and uracil — that are necessary to build DNA and RNA.

These include 14 of the 20 amino acids that life on Earth uses to build proteins and all four of the ring-shaped molecules that make up DNA - adenine, guanine, cytosine and thymine.

Nucleotides are composed of three distinctive parts: a sugar molecule, a phosphate group and one of the four nucleobases adenine, thymine, guanine and cytosine.

For example, exposure to water can cause a chemical reaction called deamination that changes the nucleotide cytosine such that it appears to be the nucleotide thymine upon analysis.

One loose end, Sasselov acknowledges, is that RAO has only been shown to lead to the synthesis of two of RNA’s four nucleotides, cytosine and uracil.