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Reaction genealogy of purines and pyrimidines starting from three simple amino-substituted heterocycles. Shown are 2,6-diaminopurine (Dap), adenine (A), and 2,4-diaminopyrimidine (Dpy), all considered to be prebiotically plausible heterocycles, which can in principle give rise to many different types of nucleobases, including the native alphabet and its surrogates. The reactions shown here are all well known and occur in contemporary biochemistry.
