Peptide nucleic acid has been hypothesised as the primordial genetic material: Nelson, KE, M Levy, and SL Miller. 2000. Proc Natl Acad Sci 97(8):3868-3871. Peptide Nucleic Acids rather than RNA may have been the First Genetic Material. Nielson, PE. 1993. Orig Life Evol Biosph 23(5-6):323-327. Peptide nucleic acid (PNA): a model structure for the primordial genetic material? It has never been seen in nature (although it has not been looked for, as far as I know) and it is usually thought that PNA was a transitory genetic material to be replaced by RNA and finally DNA. The structure of synthetic PNA, and how it base pairs with DNA (which allows a comparison of the structure of PNA to DNA) is shown here (also a general structure of a polypeptide is shown.): http://employees.csbsju.edu/hjakubowski/classes/ch331/bind/peptideNA.gif My biochemistry and organic chemistry are weak. It seems that there must be a way to chemically distinguish PNA from protein and DNA. Like, some in vitro reaction that would work with PNA but not the others. Can anyone help me figure out what this reaction might be? edit: The bases are attached to the backbone via amide bonds in PNA. Could these bonds be chemically broken - releasing the bases - in some way, a way that wouldn't relese bases from the phosphodiester backbone in RNA or DNA?