Basis of differentiation | Transition mutation | Transversion mutation |
Definition | Transition mutation is a type of point mutation in which one base (either purine or pyrimidine) is replaced by another base of the same class (purine or pyrimidine). | Transversion mutation is a type of point mutation in which a purine base is replaced by a pyrimidine base and pyrimidine base is replaced by a purine base. |
Ring Structure Change | The ring structure of the nitrogenous base does not undergo any change in a transition mutation | The ring structure of the nitrogenous base changes in a transversion mutation |
Significance | The base change occurs within the same class. | The base changes from one class to another. |
Types | There are 8 possible types of transitions. | There are 4 possible types of transversions. |
Possibility per Base | Each base can only undergo a single type of transition. | A base can undergo two types of transversions. |
Occurrence | Transitions occur due to oxidative deamination and tautomerization. | Transversions occur spontaneously or they may be caused due to ionizing radiation and alkylating agents. |
Occurrence in the Genome | Transition mutations are more common in the genome. | Transversion mutations are comparatively less common in the genome. |
Effect | Transitions occur as silent mutations and are less likely to result in amino acid substitutions. | Transversions have a more pronounced effect. This is because a transversion of the 3rdnucleotide of a codon typically causes the codon to degenerate. |