Skip to content
Login Register

#DNA substitution

2 public questions tagged with this topic.

Mutation and Mutagenesis

Transversion mutation involves

Transversion mutation substitutes purine for pyrimidine or vice versa, for example A→C, A→T, G→C, G→T and reciprocal changes, involving interconversion of double-ring and single-ring structures. This creates larger geometric distortion than transition, often triggering repair recognition yet when fixed causes more dramatic chemical change. Transversions can result from oxidative damage generating 8-oxo-guanine pairing with adenine or from alkylation products. Their occurrence produces stronger effects on protein coding due to greater likelihood of non-conservative amino acid replacement. This

Ref: Lehninger Principles of Biochemistry, 8th ed., Chapter 8: Transversion Base Substitutions and Structural Distortion

View Details
Mutation and Mutagenesis

Transition mutation involves

Transition mutation is subtype of base substitution where a purine is replaced by remaining purine (A↔G) or pyrimidine by remaining pyrimidine (C↔T), preserving ring type. Such changes arise from tautomeric mispairing and deamination events, for instance deamination of 5-methylcytosine producing thymine. Because purine-pyrimidine axis stays similar, helical distortion is minimal and lesions often escape detection by repair surveillance, leading to higher spontaneous frequency than transversions and influencing codon degeneracy patterns observed in molecular evolution. This principle illustrate

Ref: Lodish et al., Molecular Cell Biology, 9th ed., Chapter 9: Transition Mutations Purine-to-Purine

View Details