Peptide nucleic acids rather than RNA may have been the first genetic molecule

Kevin E. Nelson, Matthew Levy, Stanley L. Miller

Research output: Contribution to journalArticlepeer-review

191 Scopus citations


Numerous problems exist with the current thinking of RNA as the first genetic material. No plausible prebiotic processes have yet been demonstrated to produce the nucleosides or nucleotides or for efficient two-way nonenzymatic replication. Peptide nucleic acid (PNA) is a promising precursor to RNA, consisting of N-(2-aminoethyl)glycine (AEG) and the adenine, uracil, guanine, and cytosine-N-acetic acids. However, PNA has not yet been demonstrated to be prebiotic. We show here that AEG is produced directly in electric discharge reactions from CH4, N2, NH3, and H2O. Electric discharges also produce ethylenediamine, as do NH4CN polymerizations. AEG is produced from the robust Strecker synthesis with ethylenediamine. The NH4CN polymerization in the presence of glycine leads to the adenine and guanine- N9-acetic acids, and the cytosine and uracil-N1-acetic acids are produced in high yield from the reaction of cyanoacetaldehyde with hydantoic acid, rather than urea. Preliminary experiments suggest that AEG may polymerize rapidly at 100°C to give the polypeptide backbone of PNA. The ease of synthesis of the components of PNA and possibility of polymerization of AEG reinforce the possibility that PNA may have been the first genetic material.

Original languageEnglish (US)
Pages (from-to)3868-3871
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number8
StatePublished - Apr 11 2000
Externally publishedYes


  • Chemical evolution
  • First genetic material
  • Pre-RNA world
  • Prebiotic synthesis
  • RNA world

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Peptide nucleic acids rather than RNA may have been the first genetic molecule'. Together they form a unique fingerprint.

Cite this