On early Earth, a primitive polymer that could spontaneously form from likely available precursors may have preceded both RNA and DNA as the first genetic material. Here, we report that heated aqueous solutions containing 5-hydroxymethyluracil (HMU) result in oligomers of uracil, heated solutions containing 5-hydroxymethylcytosine (HMC) result in oligomers of cytosine, and heated solutions containing both HMU and HMC result in mixed oligomers of uracil and cytosine. Oligomerization of hydroxymethylated pyrimidines, which may have been abundant on the primitive Earth, might have been important in the development of simple informational polymers.
Liquid chromatography Mass spectrometry Oligomerization Prebiotic chemistry Pyrimidines
This research was supported by the NASA Pennsylvania Space Grant Consortium, NASA Astrobiology Institute via the Penn State Astrobiology Research Center (cooperative agreement #NNA09DA76A), and the NASA Astrobiology Institute via the Goddard Center for Astrobiology. We thank Prof. Jim Kubicki (Penn State) for assistance with DFT calculations. We also thank Dr. Henderson (Jim) Cleaves (Institute for Advanced Study/Tokyo Institute of Technology) for helpful discussions.
Cafferty BJ, Gallego I, Chen MC, Farley KI, Eritja R, Hud NV (2013) Efficient self-assembly in water of long noncovalent polymers by nucleobase analogues. J Am Chem Soc 135(7):2447–2450CrossRefPubMedGoogle Scholar
Callahan MP, Smith KE, Cleaves HJ, Ruzicka J, Stern JC, Glavin DP, House CH, Dworkin JP (2011) Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases. Proc Natl Acad Sci U S A 108(34):13995–13998CrossRefPubMedPubMedCentralGoogle Scholar
Cech TR, Zaug AJ, Grabowski PJ (1981) In vitro splicing of the ribosomal RNA precursor of Tetrahymena: Involvement of a guanosine nucleotide in the excision of the intervening sequence. Cell 27(3):487–496CrossRefPubMedGoogle Scholar
Joyce GF, Schwartz AW, Miller SL, Orgel LE (1987) The case for an ancestral genetic system involving simple analogues of the nucleotides. Proc Natl Acad Sci U S A 84(13):4398–4402CrossRefPubMedPubMedCentralGoogle Scholar
Larralde R, Robertson M, Miller SL (1995) Rates of decomposition of ribose and other sugars: implications for chemical evolution. Proc Natl Acad Sci U S A 92(18):8158–8160CrossRefPubMedPubMedCentralGoogle Scholar
Lazcano A, Miller SL (1996) The origin and early evolution of life: prebiotic chemistry, the pre-RNA world, and time. Cell 85(6):793–798CrossRefPubMedGoogle Scholar
Oró J (1961) Mechanism of synthesis of adenine from hydrogen cyanide under possible primitive Earth conditions. Nature 191(479):1193–1194CrossRefPubMedGoogle Scholar
Robertson MP, Miller SL (1995) Prebiotic synthesis of 5-substituted uracils: a bridge between the RNA world and the DNA-protein world. Science 268(5211):702–705CrossRefPubMedGoogle Scholar