title: An unusual base pairing between pyrimidine and pyridine nucleotides.
mesh_terms: D001482:Base Composition; D009711:Nucleotides; D011725:Pyridines; D011743:Pyrimidines
chemical_list: D009711:Nucleotides; D011725:Pyridines; D011743:Pyrimidines; C023666:pyridine