title: The effect of higher structures of macromolecules on the genetic consequences of the action of mutagens.
abstract: An explanation of some discrepancies between the known chemical data and the genetic consequences of chemical mutagenesis is proposed, based on the functional role of the higher structure of macromolecules. In a single-stranded DNA- or RNA- containing genome, some primary (induced) point mutations, even if not manifested phenotypically, can result in local disturbances of the double-helical regions. Secondary (spontaneous) mutations at the complementary site of a polynucleotide can restore the higher structure. If a certain higher structure is more significant as a selection factor than the base substitution, the secondary, phenotypically detectable, mutants can accumulate during reproduction of a mutangenized phage. The higher structure of some nucleoprotein complexes and proteins could also serve as a selection factor causing accumulation of secondary mutants.
mesh_terms: D001483:Base Sequence; D003090:Coliphages / Q000187:drug effects; D004261:DNA Replication; D004267:DNA Viruses / Q000187:drug effects; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D005815:Genetic Code; D005838:Genotype; D006898:Hydroxylamines / Q000494:pharmacology; D046911:Macromolecular Substances; D009153:Mutagens / Q000494:pharmacology*; D009154:Mutation; D009608:Nitrous Acid / Q000494:pharmacology; D010641:Phenotype; D012313:RNA; D012328:RNA Viruses / Q000187:drug effects; D012367:RNA, Viral; D011995:Recombination, Genetic; D013329:Structure-Activity Relationship
chemical_list: D004277:DNA, Single-Stranded; D004279:DNA, Viral; D006898:Hydroxylamines; D046911:Macromolecular Substances; D009153:Mutagens; D012367:RNA, Viral; D012313:RNA; D009608:Nitrous Acid